SJGames has a webpage that outlines the "Online Policy" and its copyrights/trademarks
here.
That site also has a link where you can email with questions (right beside the title of the page).
Note that: you can create free non-profit supplementary things for GURPS (like writing an adventure, or writing a character) but you cannot reproduce the game rules on their own. So as an example, if you wanted to use GURPS Realm Management rules to list 三国演义 kingdoms, or write a GURPS adventure at 赤壁之战, or write the statistics for 曹操, those would likely be OK to share for free. But if you're literally translating the GURPS rules into Chinese and then sharing those (whether for free or for money) then it would very likely be a problem.
The above is just examples, and is just based on the sort of material that people share on this forum. You should definitely refer to the Online Policy webpage and contact SJGames for confirmation.