this is not a mojoportal specific question, there are better resources for this question on the web.
I recommend do some googling for "asp.net chinese characters" and "html chinese characters" and "html chinese characters, codepage" and similar phrases and do some research about it.
It also depends on whether the Chinese text is coming from a database or being stored in a database, then the database, collation, charset are all important as well, characters can be lost on save if the database does not support the characters.
for html output you we typically use unicode/utf-8
so there are 2 areas of consideration, rendering Chinese in html and storing/retrieving from the database