diff --git a/internal/database/asset_test.go b/internal/database/asset_test.go
index b9418d9b8..4f40b8980 100644
--- a/internal/database/asset_test.go
+++ b/internal/database/asset_test.go
@@ -4,6 +4,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 
@@ -447,3 +448,37 @@ func TestAssetListFlexibleFiltersAndOldestScanPagination(t *testing.T) {
 		t.Fatalf("structured filters: total=%d assets=%#v err=%v", total, filtered, err)
 	}
 }
+
+func TestUpsertAssetsConcurrentCreatesDoNotLock(t *testing.T) {
+	db, err := NewDB(filepath.Join(t.TempDir(), "assets-concurrent.db"), zap.NewNop())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	const goroutines = 24
+	errs := make([]error, goroutines)
+	var wg sync.WaitGroup
+	for i := 0; i < goroutines; i++ {
+		wg.Add(1)
+		go func(i int) {
+			defer wg.Done()
+			asset := &Asset{Host: "https://198.51.100." + strconv.Itoa(i+1) + ":443", Source: "concurrent"}
+			_, errs[i] = db.UpsertAssets([]*Asset{asset}, "")
+		}(i)
+	}
+	wg.Wait()
+
+	for i, err := range errs {
+		if err != nil {
+			t.Fatalf("concurrent upsert %d failed: %v", i, err)
+		}
+	}
+	_, total, err := db.ListAssets(100, 0, AssetListFilter{Source: "concurrent"}, RBACListAccess{Scope: RBACScopeAll})
+	if err != nil {
+		t.Fatalf("list assets: %v", err)
+	}
+	if total != goroutines {
+		t.Fatalf("total=%d, want %d", total, goroutines)
+	}
+}
diff --git a/internal/database/database.go b/internal/database/database.go
index 35884987d..1bc519197 100644
--- a/internal/database/database.go
+++ b/internal/database/database.go
@@ -1,6 +1,7 @@
 package database
 
 import (
+	"context"
 	"database/sql"
 	"fmt"
 	"os"
@@ -47,6 +48,7 @@ func configureSQLitePragmas(db *sql.DB) error {
 // DB 数据库连接
 type DB struct {
 	*sql.DB
+	writeMu                  sync.Mutex // 串行化写事务，配合 _txlock=immediate 消除 SQLITE_BUSY
 	logger                   *zap.Logger
 	conversationArtifactsDir string
 	einoPlantaskBaseDir      string // skills_dir + plantask_rel_dir (per-conversation subdirs)
@@ -61,6 +63,52 @@ type DB struct {
 	vulnerabilityCreatedHook func(*Vulnerability)
 }
 
+// serialTx 包装 *sql.Tx：事务结束（Commit/Rollback）时释放 DB.writeMu。
+// 调用点无需感知，仍可把返回值当作 *sql.Tx 使用。
+type serialTx struct {
+	*sql.Tx
+	release func()
+	once    sync.Once
+}
+
+func (t *serialTx) Commit() error {
+	err := t.Tx.Commit()
+	t.releaseOnce()
+	return err
+}
+
+func (t *serialTx) Rollback() error {
+	err := t.Tx.Rollback()
+	t.releaseOnce()
+	return err
+}
+
+func (t *serialTx) releaseOnce() {
+	if t.release != nil {
+		t.once.Do(t.release)
+	}
+}
+
+// Begin 启动写事务。写事务在进程内严格串行：获取 writeMu 后才执行
+// BEGIN IMMEDIATE（由 DSN _txlock=immediate 保证），提交/回滚后释放。
+func (db *DB) Begin() (*serialTx, error) {
+	return db.BeginTx(context.Background(), nil)
+}
+
+// BeginTx 与 Begin 相同，支持显式事务选项。
+func (db *DB) BeginTx(ctx context.Context, opts *sql.TxOptions) (*serialTx, error) {
+	if db == nil || db.DB == nil {
+		return nil, fmt.Errorf("数据库未初始化")
+	}
+	db.writeMu.Lock()
+	tx, err := db.DB.BeginTx(ctx, opts)
+	if err != nil {
+		db.writeMu.Unlock()
+		return nil, err
+	}
+	return &serialTx{Tx: tx, release: db.writeMu.Unlock}, nil
+}
+
 // startPassiveCheckpointLoop 启动后台 PASSIVE checkpoint 循环。
 func (db *DB) startPassiveCheckpointLoop(name string) {
 	if sqlitePassiveCheckpointInterval <= 0 || db == nil || db.DB == nil {
@@ -122,7 +170,7 @@ func (db *DB) runPassiveCheckpoint(trigger string) {
 
 // NewDB 创建数据库连接
 func NewDB(dbPath string, logger *zap.Logger) (*DB, error) {
-	db, err := sql.Open("sqlite3", dbPath+"?_journal_mode=WAL&_foreign_keys=1&_busy_timeout=5000&_synchronous=NORMAL")
+	db, err := sql.Open("sqlite3", dbPath+"?_journal_mode=WAL&_foreign_keys=1&_busy_timeout=5000&_synchronous=NORMAL&_txlock=immediate")
 	if err != nil {
 		return nil, fmt.Errorf("打开数据库失败: %w", err)
 	}
@@ -1671,7 +1719,7 @@ func (db *DB) migrateC2ListenersTable() error {
 
 // NewKnowledgeDB 创建知识库数据库连接（只包含知识库相关的表）
 func NewKnowledgeDB(dbPath string, logger *zap.Logger) (*DB, error) {
-	sqlDB, err := sql.Open("sqlite3", dbPath+"?_journal_mode=WAL&_foreign_keys=1&_busy_timeout=5000&_synchronous=NORMAL")
+	sqlDB, err := sql.Open("sqlite3", dbPath+"?_journal_mode=WAL&_foreign_keys=1&_busy_timeout=5000&_synchronous=NORMAL&_txlock=immediate")
 	if err != nil {
 		return nil, fmt.Errorf("打开知识库数据库失败: %w", err)
 	}
diff --git a/internal/database/rbac.go b/internal/database/rbac.go
index 28e865022..3c4cba11b 100644
--- a/internal/database/rbac.go
+++ b/internal/database/rbac.go
@@ -349,7 +349,7 @@ func (db *DB) BootstrapRBAC(adminPasswordHash string, permissions map[string]str
 	return tx.Commit()
 }
 
-func grantSystemRolePermissions(tx *sql.Tx, permissions map[string]string) error {
+func grantSystemRolePermissions(tx *serialTx, permissions map[string]string) error {
 	now := time.Now()
 	// System roles are immutable and owned by the application. Rebuild their
 	// grants deterministically so policy tightening also removes permissions
diff --git a/internal/database/vulnerability.go b/internal/database/vulnerability.go
index 2eede0fa4..e2f5072d4 100644
--- a/internal/database/vulnerability.go
+++ b/internal/database/vulnerability.go
@@ -392,7 +392,7 @@ func (db *DB) DeleteVulnerability(id string) error {
 	return nil
 }
 
-func collectVulnerabilityConversationIDs(tx *sql.Tx, where string, args []interface{}) ([]string, error) {
+func collectVulnerabilityConversationIDs(tx *serialTx, where string, args []interface{}) ([]string, error) {
 	rows, err := tx.Query(`SELECT DISTINCT COALESCE(conversation_id,'') FROM vulnerabilities `+where, args...)
 	if err != nil {
 		return nil, fmt.Errorf("查询受影响漏洞会话失败: %w", err)