diff --git a/supply-api/internal/audit/model/alert_test.go b/supply-api/internal/audit/model/alert_test.go
new file mode 100644
index 00000000..ad512630
--- /dev/null
+++ b/supply-api/internal/audit/model/alert_test.go
@@ -0,0 +1,219 @@
+package model
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// TestNewAlert 测试创建告警
+func TestNewAlert(t *testing.T) {
+	alert := NewAlert("test-alert", AlertTypeSecurity, AlertLevelWarning, "12345", "Test Title", "Test Message")
+
+	assert.NotEmpty(t, alert.AlertID)
+	assert.Equal(t, "test-alert", alert.AlertName)
+	assert.Equal(t, AlertTypeSecurity, alert.AlertType)
+	assert.Equal(t, AlertLevelWarning, alert.AlertLevel)
+	assert.Equal(t, int64(12345), alert.TenantID)
+	assert.Equal(t, "Test Title", alert.Title)
+	assert.Equal(t, "Test Message", alert.Message)
+	assert.Equal(t, AlertStatusActive, alert.Status)
+	assert.True(t, alert.NotifyEnabled)
+	assert.NotZero(t, alert.CreatedAt)
+	assert.NotNil(t, alert.Metadata)
+	assert.NotNil(t, alert.Tags)
+}
+
+// TestParseTenantID 测试租户ID解析
+func TestParseTenantID(t *testing.T) {
+	testCases := []struct {
+		input    string
+		expected int64
+	}{
+		{"12345", 12345},
+		{"0", 0},
+		{"", 0},
+		{"abc", 0},
+		{"123abc456", 123456},
+		{"000", 0},
+		{"00123", 123},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.input, func(t *testing.T) {
+			result := parseTenantID(tc.input)
+			assert.Equal(t, tc.expected, result)
+		})
+	}
+}
+
+// TestAlert_IsActive 测试告警活跃状态检测
+func TestAlert_IsActive(t *testing.T) {
+	alert := &Alert{Status: AlertStatusActive}
+	assert.True(t, alert.IsActive())
+
+	alert.Status = AlertStatusResolved
+	assert.False(t, alert.IsActive())
+
+	alert.Status = AlertStatusAcknowledged
+	assert.False(t, alert.IsActive())
+
+	alert.Status = AlertStatusSuppressed
+	assert.False(t, alert.IsActive())
+}
+
+// TestAlert_IsResolved 测试告警已解决状态检测
+func TestAlert_IsResolved(t *testing.T) {
+	alert := &Alert{Status: AlertStatusResolved}
+	assert.True(t, alert.IsResolved())
+
+	alert.Status = AlertStatusActive
+	assert.False(t, alert.IsResolved())
+}
+
+// TestAlert_Resolve 测试解决告警
+func TestAlert_Resolve(t *testing.T) {
+	alert := &Alert{
+		Status:     AlertStatusActive,
+		UpdatedAt:  time.Now().Add(-time.Hour),
+	}
+
+	alert.Resolve("user123", "Fixed the issue")
+
+	assert.Equal(t, AlertStatusResolved, alert.Status)
+	assert.NotNil(t, alert.ResolvedAt)
+	assert.Equal(t, "user123", alert.ResolvedBy)
+	assert.Equal(t, "Fixed the issue", alert.ResolveNote)
+	assert.True(t, alert.UpdatedAt.After(time.Now().Add(-time.Minute)))
+}
+
+// TestAlert_Acknowledge 测试确认告警
+func TestAlert_Acknowledge(t *testing.T) {
+	alert := &Alert{Status: AlertStatusActive}
+	originalTime := alert.UpdatedAt
+
+	alert.Acknowledge()
+
+	assert.Equal(t, AlertStatusAcknowledged, alert.Status)
+	assert.True(t, alert.UpdatedAt.After(originalTime) || alert.UpdatedAt.Equal(originalTime))
+}
+
+// TestAlert_Suppress 测试抑制告警
+func TestAlert_Suppress(t *testing.T) {
+	alert := &Alert{Status: AlertStatusActive}
+	originalTime := alert.UpdatedAt
+
+	alert.Suppress()
+
+	assert.Equal(t, AlertStatusSuppressed, alert.Status)
+	assert.True(t, alert.UpdatedAt.After(originalTime) || alert.UpdatedAt.Equal(originalTime))
+}
+
+// TestAlert_UpdateLastSeen 测试更新最后出现时间
+func TestAlert_UpdateLastSeen(t *testing.T) {
+	oldTime := time.Now().Add(-time.Hour)
+	alert := &Alert{LastSeenAt: oldTime, UpdatedAt: oldTime}
+
+	alert.UpdateLastSeen()
+
+	assert.True(t, alert.LastSeenAt.After(oldTime))
+	assert.True(t, alert.UpdatedAt.After(oldTime))
+}
+
+// TestAlert_AddEventID 测试添加关联事件ID
+func TestAlert_AddEventID(t *testing.T) {
+	alert := &Alert{}
+
+	// First event ID should set both EventID and EventIDs[0]
+	alert.AddEventID("evt-001")
+	assert.Equal(t, "evt-001", alert.EventID)
+	assert.Len(t, alert.EventIDs, 1)
+	assert.Equal(t, "evt-001", alert.EventIDs[0])
+
+	// Second event ID should only add to EventIDs
+	alert.AddEventID("evt-002")
+	assert.Equal(t, "evt-001", alert.EventID) // First one preserved
+	assert.Len(t, alert.EventIDs, 2)
+	assert.Equal(t, "evt-002", alert.EventIDs[1])
+}
+
+// TestAlert_SetMetadata 测试设置元数据
+func TestAlert_SetMetadata(t *testing.T) {
+	alert := &Alert{}
+
+	// Set metadata when nil
+	alert.SetMetadata("key1", "value1")
+	assert.Equal(t, "value1", alert.Metadata["key1"])
+
+	// Set another key
+	alert.SetMetadata("key2", 123)
+	assert.Equal(t, "value1", alert.Metadata["key1"])
+	assert.Equal(t, 123, alert.Metadata["key2"])
+
+	// Overwrite existing key
+	alert.SetMetadata("key1", "newvalue")
+	assert.Equal(t, "newvalue", alert.Metadata["key1"])
+}
+
+// TestAlert_AddTag 测试添加标签
+func TestAlert_AddTag(t *testing.T) {
+	alert := &Alert{}
+
+	// Add first tag
+	alert.AddTag("security")
+	assert.Contains(t, alert.Tags, "security")
+
+	// Add another tag
+	alert.AddTag("urgent")
+	assert.Contains(t, alert.Tags, "security")
+	assert.Contains(t, alert.Tags, "urgent")
+
+	// Add duplicate tag - should not add again
+	alert.AddTag("security")
+	assert.Equal(t, 2, len(alert.Tags))
+}
+
+// TestAlert_AddTag_NoDuplicate 测试添加重复标签
+func TestAlert_AddTag_NoDuplicate(t *testing.T) {
+	alert := &Alert{Tags: []string{"existing"}}
+
+	alert.AddTag("existing")
+	assert.Len(t, alert.Tags, 1)
+}
+
+// TestAlert_Constants 测试告警常量
+func TestAlert_Constants(t *testing.T) {
+	// Alert levels
+	assert.Equal(t, "info", AlertLevelInfo)
+	assert.Equal(t, "warning", AlertLevelWarning)
+	assert.Equal(t, "error", AlertLevelError)
+	assert.Equal(t, "critical", AlertLevelCritical)
+
+	// Alert statuses
+	assert.Equal(t, "active", AlertStatusActive)
+	assert.Equal(t, "resolved", AlertStatusResolved)
+	assert.Equal(t, "acknowledged", AlertStatusAcknowledged)
+	assert.Equal(t, "suppressed", AlertStatusSuppressed)
+
+	// Alert types
+	assert.Equal(t, "security", AlertTypeSecurity)
+	assert.Equal(t, "invariant", AlertTypeInvariant)
+	assert.Equal(t, "credential", AlertTypeCredential)
+	assert.Equal(t, "authentication", AlertTypeAuthentication)
+	assert.Equal(t, "authorization", AlertTypeAuthorization)
+	assert.Equal(t, "quota", AlertTypeQuota)
+}
+
+// TestGenerateAlertID 测试告警ID生成
+func TestGenerateAlertID(t *testing.T) {
+	id1 := generateAlertID()
+	id2 := generateAlertID()
+
+	// Each ID should be unique
+	assert.NotEqual(t, id1, id2)
+
+	// ID should start with ALT-
+	assert.Contains(t, id1, "ALT-")
+	assert.Contains(t, id2, "ALT-")
+}