我解决了:
this.role3D = Laya.MeshSprite3D.load("3d/ben/Export.lh");
scene.addChild(this.role3D);
this.role3D.on(Laya.Event.HIERARCHY_LOADED,this,function(){
this.role3D.transform.scale = new Laya.Vector3(0.7,0.7,0.7);
this.role3D.transform.position = new Laya.Vector3(0,1.2,0);
}