Hi Xiaowei,
Please take a look at the following wiki page:
http://wiki.wireshark.org/Development/TranslationsThe conclusion section of the above article says:
"Translating all the dissector output is practically impossible. But
without this, it might not make real sense to translate other parts. So
in the end the effort of translating Wireshark might better be spent
for some other work."
I also translated some small projects to Chinese, and I understand that the translation work is not that trivial, and the maintenance is even harder.