I found a simple solution: re-save the subtitle file as Unicode encoding.
Open the subtitle file in MS Word,
go to "Tools" menu,
choose "Options",
Then in the "General" tab, click on "Web Options"
In the Web Option dialog, choose "Encoding" tab.
Set "Save this document as" choice to be "Unicode".
Then click save button to save the file.
After this, the subtitle will be showing as the right chinese word.
