diff --git a/internal/provider/alipay/alipay.go b/internal/provider/alipay/alipay.go
new file mode 100644
index 0000000..ecf6dd2
--- /dev/null
+++ b/internal/provider/alipay/alipay.go
@@ -0,0 +1,152 @@
+// Package alipay adapts Alipay web payment (page/wap) to provider.Provider,
+// porting v1 internal/channel/alipay.go's verify/query logic. The *alipay.Client
+// (with app private key + Alipay public key) is built from env credentials at
+// assembly time and injected, so verify_callback/query hold their own credentials.
+package alipay
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"time"
+
+	sw "github.com/smartwalle/alipay/v3"
+
+	"github.com/wangjia/pay/internal/money"
+	"github.com/wangjia/pay/internal/provider"
+)
+
+// gmtPaymentLayout 支付宝 gmt_payment/gmt_create 等时间字段格式,固定北京时间(无时区位),
+// 用 FixedZone 而非 LoadLocation("Asia/Shanghai") 避免依赖运行环境是否内置 tzdata。
+const gmtPaymentLayout = "2006-01-02 15:04:05"
+
+var cst = time.FixedZone("CST", 8*3600)
+
+type Provider struct{ client *sw.Client }
+
+func New(client *sw.Client) *Provider { return &Provider{client: client} }
+
+func (p *Provider) Method() string { return "alipay" }
+
+func (p *Provider) Capabilities() provider.Capabilities {
+	return provider.Capabilities{
+		RenderTypes:      []provider.RenderType{provider.RenderRedirect},
+		SupportsRefund:   false, // 退款 P4
+		SettleCurrencies: []string{"CNY"},
+		Regions:          []string{"cn"},
+	}
+}
+
+func (p *Provider) Create(_ context.Context, req provider.CreateRequest) (*provider.Session, error) {
+	if req.Currency != "CNY" {
+		return nil, fmt.Errorf("alipay: 仅支持 CNY, got %s", req.Currency)
+	}
+	amount, err := money.Format(req.AmountMinor, "CNY")
+	if err != nil {
+		return nil, err
+	}
+	var payURL *url.URL
+	if req.Metadata["is_mobile"] == "1" {
+		wp := sw.TradeWapPay{}
+		wp.OutTradeNo = req.OutTradeNo
+		wp.Subject = req.Subject
+		wp.TotalAmount = amount
+		wp.ProductCode = "QUICK_WAP_WAY"
+		wp.ReturnURL = req.ReturnURL
+		payURL, err = p.client.TradeWapPay(wp)
+	} else {
+		pp := sw.TradePagePay{}
+		pp.OutTradeNo = req.OutTradeNo
+		pp.Subject = req.Subject
+		pp.TotalAmount = amount
+		pp.ProductCode = "FAST_INSTANT_TRADE_PAY"
+		pp.ReturnURL = req.ReturnURL
+		pp.QRPayMode = "2" // 跳转到完整扫码收银台(迁移 v1 语义)
+		payURL, err = p.client.TradePagePay(pp)
+	}
+	if err != nil {
+		return nil, fmt.Errorf("alipay: 下单失败: %w", err)
+	}
+	return &provider.Session{
+		ProviderRef: req.OutTradeNo, // 支付宝以 out_trade_no 归位
+		RenderType:  provider.RenderRedirect,
+		Payload:     map[string]any{"url": payURL.String()},
+	}, nil
+}
+
+func (p *Provider) VerifyCallback(ctx context.Context, in provider.CallbackInput) (*provider.PaidEvent, error) {
+	form, err := url.ParseQuery(string(in.Raw))
+	if err != nil {
+		return nil, fmt.Errorf("alipay: 解析回调表单失败: %w", err)
+	}
+	// smartwalle/alipay v3.2.29 的 DecodeNotification 签名是 (ctx, values),
+	// 内部用已加载支付宝公钥验签(见 v1 internal/channel/alipay.go 同用法)。
+	noti, err := p.client.DecodeNotification(ctx, form)
+	if err != nil {
+		return nil, fmt.Errorf("alipay: 回调验签失败: %w", err)
+	}
+	paidAt := parseGmtPayment(noti.GmtPayment)
+	return notifyToEvent(noti.OutTradeNo, string(noti.TradeStatus), noti.TotalAmount, paidAt, in.Raw)
+}
+
+func (p *Provider) Query(ctx context.Context, req provider.QueryRequest) (*provider.PaidEvent, error) {
+	rsp, err := p.client.TradeQuery(ctx, sw.TradeQuery{OutTradeNo: req.OutTradeNo})
+	if err != nil {
+		return nil, fmt.Errorf("alipay: 查单失败: %w", err)
+	}
+	if rsp.IsFailure() {
+		// 交易不存在等:视为未命中(pending),交管线继续轮询。
+		return &provider.PaidEvent{ProviderRef: req.ProviderRef, Status: provider.PaidPending}, nil
+	}
+	// TradeQueryRsp 不带 gmt_payment(只有异步通知才有);查单场景 PaidAt 留 nil,
+	// 由 settle 按 D4-A3 兜底用收到时间——不用 SendPayDate("打款给卖家时间"),
+	// 那是结算时点,不是买家付款时点,拿来充 PaidAt 会误导对账。
+	ev, err := notifyToEvent(rsp.OutTradeNo, string(rsp.TradeStatus), rsp.TotalAmount, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	ev.ProviderRef = req.ProviderRef
+	return ev, nil
+}
+
+// parseGmtPayment 解析支付宝 "2006-01-02 15:04:05" 格式的付款时间(固定北京时间,无时区位)。
+// 为空或解析失败均返回 nil——交 settle 按 D4-A3 兜底用收到时间,不因此让 VerifyCallback 报错。
+func parseGmtPayment(s string) *time.Time {
+	if s == "" {
+		return nil
+	}
+	t, err := time.ParseInLocation(gmtPaymentLayout, s, cst)
+	if err != nil {
+		return nil
+	}
+	return &t
+}
+
+func notifyToEvent(outTradeNo, tradeStatus, totalAmount string, paidAt *time.Time, raw []byte) (*provider.PaidEvent, error) {
+	// 支付宝交易状态四态(sw.TradeStatus* 全集)归一化:
+	//   WAIT_BUYER_PAY(等待付款)→ pending;TRADE_SUCCESS/TRADE_FINISHED → succeeded;
+	//   TRADE_CLOSED(超时未付关闭 / 全额退款后关闭)→ failed,不留在 pending 让轮询空转到天荒地老。
+	status := provider.PaidPending
+	switch sw.TradeStatus(tradeStatus) {
+	case sw.TradeStatusSuccess, sw.TradeStatusFinished:
+		status = provider.PaidSucceeded
+	case sw.TradeStatusClosed:
+		status = provider.PaidFailed
+	}
+	var minor int64
+	if totalAmount != "" {
+		m, err := money.Parse(totalAmount, "CNY")
+		if err != nil {
+			return nil, fmt.Errorf("alipay: 金额解析失败 %q: %w", totalAmount, err)
+		}
+		minor = m
+	}
+	return &provider.PaidEvent{
+		ProviderRef:     outTradeNo,
+		Status:          status,
+		PaidAmountMinor: minor,
+		PaidCurrency:    "CNY",
+		Raw:             string(raw),
+		PaidAt:          paidAt,
+	}, nil
+}
diff --git a/internal/provider/alipay/alipay_test.go b/internal/provider/alipay/alipay_test.go
new file mode 100644
index 0000000..c61924d
--- /dev/null
+++ b/internal/provider/alipay/alipay_test.go
@@ -0,0 +1,184 @@
+package alipay_test
+
+import (
+	"context"
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/pem"
+	"net/url"
+	"sort"
+	"strings"
+	"testing"
+	"time"
+
+	sw "github.com/smartwalle/alipay/v3"
+
+	"github.com/wangjia/pay/internal/provider"
+	ali "github.com/wangjia/pay/internal/provider/alipay"
+)
+
+// 生成一对 RSA 密钥:appPriv 供 client 下单签名;aliPriv/aliPub 冒充"支付宝侧"给异步通知签名/验签。
+//
+// ⚠️ 与 brief 草稿的差异(执行时发现,已按 SDK 实际要求修正):
+// alipay 公钥 client.LoadAliPayPublicKey 内部走 ncrypto.DecodePublicKey(...).PKIX(),
+// 要求 PKIX(SubjectPublicKeyInfo)编码,不是 PKCS1 —— 用 MarshalPKCS1PublicKey 会在
+// LoadAliPayPublicKey 报 "x509: failed to parse public key (use ParsePKCS1PublicKey
+// instead for this key format)"。改用 x509.MarshalPKIXPublicKey。app 私钥走
+// ncrypto.DecodePrivateKey(...).PKCS1(),失败再退 PKCS8,MarshalPKCS1PrivateKey 不受影响。
+func genKeys(t *testing.T) (appPrivPKCS1B64, aliPrivPKCS1B64, aliPubPKIXB64 string) {
+	t.Helper()
+	app, _ := rsa.GenerateKey(rand.Reader, 2048)
+	aliK, _ := rsa.GenerateKey(rand.Reader, 2048)
+	b64 := func(b []byte) string { return base64.StdEncoding.EncodeToString(b) }
+	appPrivPKCS1B64 = b64(x509.MarshalPKCS1PrivateKey(app))
+	aliPrivPKCS1B64 = b64(x509.MarshalPKCS1PrivateKey(aliK))
+	aliPubDER, err := x509.MarshalPKIXPublicKey(&aliK.PublicKey)
+	if err != nil {
+		t.Fatalf("marshal ali pub: %v", err)
+	}
+	aliPubPKIXB64 = b64(aliPubDER)
+	return
+}
+
+func buildClient(t *testing.T, appPriv, aliPub string) *sw.Client {
+	c, err := sw.New("2021000000000000", appPriv, false) // 沙箱
+	if err != nil {
+		t.Fatalf("new client: %v", err)
+	}
+	if err := c.LoadAliPayPublicKey(aliPub); err != nil {
+		t.Fatalf("load pub: %v", err)
+	}
+	return c
+}
+
+func TestCreateRedirect(t *testing.T) {
+	appPriv, _, aliPub := genKeys(t)
+	p := ali.New(buildClient(t, appPriv, aliPub))
+
+	sess, err := p.Create(context.Background(), provider.CreateRequest{
+		OutTradeNo: "PAY-1", Subject: "Pro 年付", AmountMinor: 19900, Currency: "CNY",
+		ReturnURL: "https://x/return",
+	})
+	if err != nil {
+		t.Fatalf("create: %v", err)
+	}
+	if sess.RenderType != provider.RenderRedirect || sess.ProviderRef != "PAY-1" {
+		t.Fatalf("session = %+v", sess)
+	}
+	u, _ := sess.Payload["url"].(string)
+	if !strings.Contains(u, "alipay") {
+		t.Fatalf("url = %q 不像收银台跳转", u)
+	}
+}
+
+// 用"支付宝侧"私钥给一份通知表单签名,adapter 用装的公钥验签 → 归一化 PaidEvent。
+func TestVerifyCallbackRSA(t *testing.T) {
+	appPriv, aliPriv, aliPub := genKeys(t)
+	p := ali.New(buildClient(t, appPriv, aliPub))
+
+	form := url.Values{}
+	form.Set("out_trade_no", "PAY-1")
+	form.Set("trade_no", "2021AAA")
+	form.Set("trade_status", "TRADE_SUCCESS")
+	form.Set("total_amount", "199.00")
+	form.Set("sign_type", "RSA2")
+	form.Set("sign", signRSA2(t, aliPriv, form))
+
+	ev, err := p.VerifyCallback(context.Background(), provider.CallbackInput{Raw: []byte(form.Encode())})
+	if err != nil {
+		t.Fatalf("verify: %v", err)
+	}
+	if ev.ProviderRef != "PAY-1" || ev.Status != provider.PaidSucceeded ||
+		ev.PaidAmountMinor != 19900 || ev.PaidCurrency != "CNY" {
+		t.Fatalf("event = %+v", ev)
+	}
+	// brief 草稿的回调表单未带 gmt_payment;PaidAt 应留 nil,交 settle 按 D4-A3 兜底用收到时间。
+	if ev.PaidAt != nil {
+		t.Fatalf("未带 gmt_payment 时 PaidAt 应为 nil, got %v", ev.PaidAt)
+	}
+}
+
+// D4-A3:VerifyCallback 应从支付宝回调的 gmt_payment(北京时间,无时区位)取真实付款时间,
+// 而不是让 settle 一律回退到"收到时间"——对账时才能跟渠道流水的付款时点对得上。
+func TestVerifyCallbackRSA_PaidAtFromGmtPayment(t *testing.T) {
+	appPriv, aliPriv, aliPub := genKeys(t)
+	p := ali.New(buildClient(t, appPriv, aliPub))
+
+	form := url.Values{}
+	form.Set("out_trade_no", "PAY-2")
+	form.Set("trade_no", "2021BBB")
+	form.Set("trade_status", "TRADE_SUCCESS")
+	form.Set("total_amount", "1.00")
+	form.Set("gmt_payment", "2026-07-10 15:04:05")
+	form.Set("sign_type", "RSA2")
+	form.Set("sign", signRSA2(t, aliPriv, form))
+
+	ev, err := p.VerifyCallback(context.Background(), provider.CallbackInput{Raw: []byte(form.Encode())})
+	if err != nil {
+		t.Fatalf("verify: %v", err)
+	}
+	if ev.PaidAt == nil {
+		t.Fatal("带 gmt_payment 时 PaidAt 不应为 nil")
+	}
+	want := time.Date(2026, 7, 10, 15, 4, 5, 0, time.FixedZone("CST", 8*3600))
+	if !ev.PaidAt.Equal(want) {
+		t.Fatalf("PaidAt = %v, want %v", ev.PaidAt, want)
+	}
+}
+
+// TRADE_CLOSED(超时未付关闭/全额退款后关闭)须归一化为 failed 终态,不能停在 pending
+// 让 SyncPendingAttempts 空转到订单永远"待处理"。
+func TestVerifyCallbackRSA_ClosedIsFailed(t *testing.T) {
+	appPriv, aliPriv, aliPub := genKeys(t)
+	p := ali.New(buildClient(t, appPriv, aliPub))
+
+	form := url.Values{}
+	form.Set("out_trade_no", "PAY-3")
+	form.Set("trade_no", "2021CCC")
+	form.Set("trade_status", "TRADE_CLOSED")
+	form.Set("total_amount", "1.00")
+	form.Set("sign_type", "RSA2")
+	form.Set("sign", signRSA2(t, aliPriv, form))
+
+	ev, err := p.VerifyCallback(context.Background(), provider.CallbackInput{Raw: []byte(form.Encode())})
+	if err != nil {
+		t.Fatalf("verify: %v", err)
+	}
+	if ev.Status != provider.PaidFailed {
+		t.Fatalf("TRADE_CLOSED 应归一化为 PaidFailed, got %v", ev.Status)
+	}
+}
+
+// signRSA2 复刻支付宝签名:排序非空参数(排除 sign/sign_type),k=v&拼接,RSA-SHA256,base64。
+func signRSA2(t *testing.T, aliPrivB64 string, form url.Values) string {
+	t.Helper()
+	der, _ := base64.StdEncoding.DecodeString(aliPrivB64)
+	priv, err := x509.ParsePKCS1PrivateKey(der)
+	if err != nil {
+		t.Fatalf("parse ali priv: %v", err)
+	}
+	keys := make([]string, 0, len(form))
+	for k := range form {
+		if k == "sign" || k == "sign_type" || form.Get(k) == "" {
+			continue
+		}
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	var parts []string
+	for _, k := range keys {
+		parts = append(parts, k+"="+form.Get(k))
+	}
+	h := sha256.Sum256([]byte(strings.Join(parts, "&")))
+	sig, err := rsa.SignPKCS1v15(rand.Reader, priv, crypto.SHA256, h[:])
+	if err != nil {
+		t.Fatalf("sign: %v", err)
+	}
+	return base64.StdEncoding.EncodeToString(sig)
+}
+
+var _ = pem.Encode // 避免 import 未用(若不需要 pem 可删该 import 与本行)