The Chinese University issued a statement on Wednesday reiterating "its firm opposition to Hong Kong independence".
The move came after students set up an organisation that they said would allow members to discuss the feasibility of the city breaking away from the mainland.
The group has since started recruiting members.
In the statement, the university said that Hong Kong is an inalienable part of China and any speech or act that incites or promotes Hong Kong independence is in contravention of the Basic Law.
At the beginning of the academic year, banners and posters promoting the idea of independence went up at all of the city's universities, sparking rows and confrontations on campuses about whether or not such items are acceptable.
At that time, the Chinese University said it would tear down any pro-independence material if students didn't remove it themselves. The student union later took down a large banner that had been put up in an area it manages.
The heads of the city's 10 universities issued a joint statement in September last year over the controversy, condemning what they described as "abuses" of freedom of expression.
CUHK again warns against talk of HK independence
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