diff --git a/api/api.go b/api/api.go
index 46ca5a3863df86370686d9240bcd0c6c652b82c8..124ea35231848c2eb109f1c780cb81c9312b7e15 100644
--- a/api/api.go
+++ b/api/api.go
@@ -42,9 +42,9 @@ func LoadProgram(cfg *config.Config, appPath string) (*Program, error) {
 
 // 基于 VFS 加载程序
 // 入口 pkgPath 是包路径, 必须是 vfs.App 子包
-func LoadProgramVFS(vfs config.PkgVFS, cfg *config.Config, pkgPath string) (*Program, error) {
-	panic("TODO")
+func LoadProgramVFS(vfs *config.PkgVFS, cfg *config.Config, pkgPath string) (*Program, error) {
+	return loader.LoadProgramVFS(vfs, cfg, pkgPath)
 }
 
-// TODO: 解析 ast/语义/SSA 分阶段解析
+// TODO: 解析 ast/语义/SSA 分阶段解析, 放到 Program 中
 // TODO: Program 编译到不同后端的函数
diff --git a/internal/config/manifest.go b/internal/config/manifest.go
index 74ba05c95d3d654a96644e8cd57abc72ff2f579f..a1771c6aa91d6a488c9845a6e9b65fd050ff4ceb 100644
--- a/internal/config/manifest.go
+++ b/internal/config/manifest.go
@@ -54,6 +54,18 @@ func (p *Manifest) Clone() *Manifest {
 	return &v
 }
 
+// 简版 Manifest
+func SimpleManifest(mainPkg, appName string) *Manifest {
+	p := &Manifest{
+		MainPkg: mainPkg,
+		Pkg: Manifest_package{
+			Name:    appName,
+			Pkgpath: mainPkg,
+		},
+	}
+	return p
+}
+
 // 加载 WaModFile 文件
 // 如果 vfs 为空则从本地文件系统读取
 func LoadManifest(vfs fs.FS, appPath string) (p *Manifest, err error) {
diff --git a/internal/loader/api.go b/internal/loader/api.go
index 461423beeda499ca1f26860a0c08ad5fc9571860..691c988cd56a546071f68a2adc48a75399bea979 100644
--- a/internal/loader/api.go
+++ b/internal/loader/api.go
@@ -37,3 +37,9 @@ type Package struct {
 func LoadProgram(cfg *config.Config, appPath string) (*Program, error) {
 	return newLoader(cfg).LoadProgram(appPath)
 }
+
+// 基于 VFS 加载程序
+// 入口 pkgPath 是包路径, 必须是 vfs.App 子包
+func LoadProgramVFS(vfs *config.PkgVFS, cfg *config.Config, pkgPath string) (*Program, error) {
+	return newLoader(cfg).LoadProgramVFS(vfs, pkgPath)
+}
diff --git a/internal/loader/loader.go b/internal/loader/loader.go
index c0a06ef71e7bb2499aa6ce662a86dee40c6fb38f..183894b9838ab7b29aa0a7cc71d082b3df1e7a44 100644
--- a/internal/loader/loader.go
+++ b/internal/loader/loader.go
@@ -1,16 +1,12 @@
 // 版权 @2021 凹语言 作者。保留所有权利。
 
-// TODO: 解析 ast/语义/SSA 分阶段解析
-
 package loader
 
 import (
 	"io/fs"
-	"os"
 	"path/filepath"
 	"sort"
 	"strings"
-	"testing/fstest"
 
 	"github.com/wa-lang/wa/internal/ast"
 	"github.com/wa-lang/wa/internal/config"
@@ -29,53 +25,47 @@ type _Loader struct {
 }
 
 func newLoader(cfg *config.Config) *_Loader {
-	p := &_Loader{
+	return &_Loader{
 		cfg: *cfg.Clone(),
 		prog: &Program{
 			Pkgs: make(map[string]*Package),
 		},
 	}
-
-	return p
 }
 
-// 加载程序
 func (p *_Loader) LoadProgram(appPath string) (*Program, error) {
 	logger.Tracef(&config.EnableTrace_loader, "cfg: %+v", p.cfg)
 	logger.Tracef(&config.EnableTrace_loader, "appPath: %s", appPath)
 
+	vfs, manifest, err := loadProgramMeta(&p.cfg, appPath)
+	if err != nil {
+		logger.Tracef(&config.EnableTrace_loader, "err: %v", err)
+		return nil, err
+	}
+
+	return p.loadProgram(vfs, manifest)
+}
+
+func (p *_Loader) LoadProgramVFS(vfs *config.PkgVFS, appPath string) (*Program, error) {
 	manifest, err := config.LoadManifest(nil, appPath)
 	if err != nil {
 		logger.Tracef(&config.EnableTrace_loader, "err: %v", err)
 		return nil, err
 	}
 
+	return p.loadProgram(vfs, manifest)
+}
+
+// 加载程序
+func (p *_Loader) loadProgram(vfs *config.PkgVFS, manifest *config.Manifest) (*Program, error) {
+	logger.DumpFS(&config.EnableTrace_loader, "vfs.app", vfs.App, ".")
 	logger.Tracef(&config.EnableTrace_loader, "manifest: %s", manifest.JSONString())
 
+	p.vfs = *vfs
 	p.prog.Cfg = &p.cfg
 	p.prog.Manifest = manifest
 	p.prog.Fset = token.NewFileSet()
 
-	if p.vfs.App == nil {
-		p.vfs.App = os.DirFS(filepath.Join(p.prog.Manifest.Root, "src"))
-	}
-
-	logger.DumpFS(&config.EnableTrace_loader, "p.vfs.App", p.vfs.App, ".")
-
-	if p.vfs.Std == nil {
-		if p.cfg.WaRoot != "" {
-			p.vfs.Std = os.DirFS(filepath.Join(p.cfg.WaRoot, "src"))
-		} else {
-			p.vfs.Std = waroot.GetFS()
-		}
-	}
-	if p.vfs.Vendor == nil {
-		p.vfs.Vendor = os.DirFS(filepath.Join(p.prog.Manifest.Root, "vendor"))
-		if p.vfs.Vendor == nil {
-			p.vfs.Vendor = make(fstest.MapFS) // empty fs
-		}
-	}
-
 	// import "runtime"
 	logger.Trace(&config.EnableTrace_loader, "import runtime")
 	if _, err := p.Import("runtime"); err != nil {
diff --git a/internal/loader/vfs.go b/internal/loader/vfs.go
new file mode 100644
index 0000000000000000000000000000000000000000..e772cfccc040f4a57c43612144d41819ad6dc69e
--- /dev/null
+++ b/internal/loader/vfs.go
@@ -0,0 +1,52 @@
+// 版权 @2021 凹语言 作者。保留所有权利。
+
+package loader
+
+import (
+	"os"
+	"path/filepath"
+	"testing/fstest"
+
+	"github.com/wa-lang/wa/internal/config"
+	"github.com/wa-lang/wa/internal/logger"
+	"github.com/wa-lang/wa/internal/waroot"
+)
+
+// 根据路径加载需要的 vfs 和 manifest
+func loadProgramMeta(cfg *config.Config, appPath string) (
+	vfs *config.PkgVFS,
+	manifest *config.Manifest,
+	err error,
+) {
+	logger.Tracef(&config.EnableTrace_loader, "cfg: %+v", cfg)
+	logger.Tracef(&config.EnableTrace_loader, "appPath: %s", appPath)
+
+	manifest, err = config.LoadManifest(nil, appPath)
+	if err != nil {
+		logger.Tracef(&config.EnableTrace_loader, "err: %v", err)
+		return nil, nil, err
+	}
+
+	logger.Tracef(&config.EnableTrace_loader, "manifest: %s", manifest.JSONString())
+
+	vfs = new(config.PkgVFS)
+	if vfs.App == nil {
+		vfs.App = os.DirFS(filepath.Join(manifest.Root, "src"))
+	}
+
+	if vfs.Std == nil {
+		if cfg.WaRoot != "" {
+			vfs.Std = os.DirFS(filepath.Join(cfg.WaRoot, "src"))
+		} else {
+			vfs.Std = waroot.GetFS()
+		}
+	}
+	if vfs.Vendor == nil {
+		vfs.Vendor = os.DirFS(filepath.Join(manifest.Root, "vendor"))
+		if vfs.Vendor == nil {
+			vfs.Vendor = make(fstest.MapFS) // empty fs
+		}
+	}
+
+	return
+}