There's a documentary called Queer China, 'Comrade' China.
Does it have to be Chinese? Or can it be from Hong Kong and Taiwan? Well..
Farewell My Concubine (Chinese)
East Palace, West Palace (Chinese)
Lan Yu (Hong Kong-Chinese film)
Happy Together (1997, Hong Kong film)
Spider Lilies (Taiwan)
The Wedding Banquet (Taiwan)
These are the only ones I can remember, most of them are in my PTW list or my On Hold list, so I can really talk about their quality, all I can say is that they all have homosexual themes, and some of them have explicit scenes like Lan Yu, which has full-frontal male nudity.