@Winds As you are Chinese, I'm assuming your computer's system language is also set to Chinese. Sadly, the current Pokémon World Online client is not Unicode-friendly; and if your computer uses an alphabet or has accents that differ from a general English character set, the client will easily get confused as to what is being typed. This also breaks the ability to log in, as PWO encrypts passwords using symbols, and your system is not returning the output it expects.
The solution is to change your system's default language for non-Unicode programs. Instructions on how to do so can be found at our wiki: