Hi Ming,
I looked at the .ply file you posted. It contains only points with no face data. i am not sure what is crashing SketchUp, but my .ply importer does not import points - it uses the points to create faces. There is no face data in the .ply file.
Do you want to view the point cloud in SketchUp, or did you want to view a mesh made from the point data in SketchUp?
My extension can not create a mesh from points. Use MeshLab to create a mesh from the point data. Then you can export the mesh and try to import in SketchUp again. It is probably a good idea to clean and simplify the mesh in MeshLab before exporting.