diff --git a/tools/goctl/rpc/generator/gencall_test.go b/tools/goctl/rpc/generator/gencall_test.go
new file mode 100644
index 000000000..deb773a28
--- /dev/null
+++ b/tools/goctl/rpc/generator/gencall_test.go
@@ -0,0 +1,125 @@
+package generator
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/emicklei/proto"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	conf "github.com/zeromicro/go-zero/tools/goctl/config"
+	"github.com/zeromicro/go-zero/tools/goctl/rpc/parser"
+	"github.com/zeromicro/go-zero/tools/goctl/util/stringx"
+)
+
+// mockDirContext is a minimal DirContext for unit-testing genCallGroup.
+type mockDirContext struct {
+	callDir Dir
+	pbDir   Dir
+	protoGo Dir
+}
+
+func (m *mockDirContext) GetCall() Dir                   { return m.callDir }
+func (m *mockDirContext) GetEtc() Dir                    { return Dir{} }
+func (m *mockDirContext) GetInternal() Dir               { return Dir{} }
+func (m *mockDirContext) GetConfig() Dir                 { return Dir{} }
+func (m *mockDirContext) GetLogic() Dir                  { return Dir{} }
+func (m *mockDirContext) GetServer() Dir                 { return Dir{} }
+func (m *mockDirContext) GetSvc() Dir                    { return Dir{} }
+func (m *mockDirContext) GetPb() Dir                     { return m.pbDir }
+func (m *mockDirContext) GetProtoGo() Dir                { return m.protoGo }
+func (m *mockDirContext) GetMain() Dir                   { return Dir{} }
+func (m *mockDirContext) GetServiceName() stringx.String { return stringx.From("test") }
+func (m *mockDirContext) SetPbDir(pbDir, grpcDir string) {}
+
+// TestGenCallGroup_OnlyUsedTypesAliased verifies that in multi-service mode each
+// generated client file contains type aliases only for the message types actually
+// used by that service's RPCs (fix for issue #5481).
+func TestGenCallGroup_OnlyUsedTypesAliased(t *testing.T) {
+	tmpDir := t.TempDir()
+	callBase := filepath.Join(tmpDir, "call")
+	pbBase := filepath.Join(tmpDir, "pb")
+
+	// Pre-create subdirs that genCallGroup will write into.
+	require.NoError(t, os.MkdirAll(filepath.Join(callBase, "servicea"), 0755))
+	require.NoError(t, os.MkdirAll(filepath.Join(callBase, "serviceb"), 0755))
+	require.NoError(t, os.MkdirAll(pbBase, 0755))
+
+	mctx := &mockDirContext{
+		callDir: Dir{
+			Filename: callBase,
+			Package:  "example.com/multitest/call",
+			Base:     "call",
+			GetChildPackage: func(childPath string) (string, error) {
+				// Return a package path whose Base() is the lowercase service name.
+				return filepath.Join(callBase, strings.ToLower(childPath)), nil
+			},
+		},
+		pbDir: Dir{
+			Filename: pbBase,
+			Package:  "example.com/multitest/pb",
+			Base:     "pb",
+		},
+		protoGo: Dir{
+			// Must differ from "servicea"/"serviceb" so isCallPkgSameToPbPkg stays false
+			// and alias generation is triggered.
+			Filename: pbBase,
+			Package:  "example.com/multitest/pb",
+			Base:     "pb",
+		},
+	}
+
+	// Proto with two services that use completely disjoint message types.
+	protoData := parser.Proto{
+		Name:      "multi.proto",
+		PbPackage: "pb",
+		Message: []parser.Message{
+			{Message: &proto.Message{Name: "AReq"}},
+			{Message: &proto.Message{Name: "AResp"}},
+			{Message: &proto.Message{Name: "BReq"}},
+			{Message: &proto.Message{Name: "BResp"}},
+		},
+		Service: parser.Services{
+			{
+				Service: &proto.Service{Name: "ServiceA"},
+				RPC: []*parser.RPC{
+					{RPC: &proto.RPC{Name: "DoA", RequestType: "AReq", ReturnsType: "AResp"}},
+				},
+			},
+			{
+				Service: &proto.Service{Name: "ServiceB"},
+				RPC: []*parser.RPC{
+					{RPC: &proto.RPC{Name: "DoB", RequestType: "BReq", ReturnsType: "BResp"}},
+				},
+			},
+		},
+	}
+
+	cfg, err := conf.NewConfig("")
+	require.NoError(t, err)
+
+	g := NewGenerator("gozero", false)
+	require.NoError(t, g.genCallGroup(mctx, protoData, cfg))
+
+	// servicea/servicea.go — aliases for AReq/AResp only
+	aContent, err := os.ReadFile(filepath.Join(callBase, "servicea", "servicea.go"))
+	require.NoError(t, err)
+	aFile := string(aContent)
+
+	assert.Contains(t, aFile, "AReq = pb.AReq", "ServiceA file should alias AReq")
+	assert.Contains(t, aFile, "AResp = pb.AResp", "ServiceA file should alias AResp")
+	assert.NotContains(t, aFile, "BReq = pb.BReq", "ServiceA file must not alias BReq")
+	assert.NotContains(t, aFile, "BResp = pb.BResp", "ServiceA file must not alias BResp")
+
+	// serviceb/serviceb.go — aliases for BReq/BResp only
+	bContent, err := os.ReadFile(filepath.Join(callBase, "serviceb", "serviceb.go"))
+	require.NoError(t, err)
+	bFile := string(bContent)
+
+	assert.Contains(t, bFile, "BReq = pb.BReq", "ServiceB file should alias BReq")
+	assert.Contains(t, bFile, "BResp = pb.BResp", "ServiceB file should alias BResp")
+	assert.NotContains(t, bFile, "AReq = pb.AReq", "ServiceB file must not alias AReq")
+	assert.NotContains(t, bFile, "AResp = pb.AResp", "ServiceB file must not alias AResp")
+}