Tsui Sze Man (Chinese: 徐四民; pinyin: Xú Sìmín, 3 July 1914 – 9 September 2007) was a pro-Beijing loyalist and magazine publisher based in Hong Kong. He was nicknamed "Big Cannon Tsui" for his outspoken and sometimes controversial views. He was known as a staunch supporter of Beijing's policies in Hong Kong.
Tsui was born in 1914 in Burma (present day Myanmar). Despite his birth in Burma, Tsui spent the majority of his life either in mainland China or Hong Kong. Tsui attended school at Xiamen University in Fujian province.
Tsui returned to his birthplace, Burma, in the 1940s and founded the New Rangoon News. He returned to Communist China in 1964. Tsui finally settled permanently in Hong Kong in 1977. Once in Hong Kong, Tsui began publishing The Mirror, a pro-Beijing magazine which supported the policies of the mainland.
Tsui was known for his controversial opinions. In 1998, he heavily criticized RTHK, a Hong Kong government run radio station, for being too critical of the Hong Kong and Chinese administrations. Tsui urged Hong Kong officials to censor RTHK.