The Library and Archives Canada website, Immigration from China, 1885-1949, is a major source of genealogical information. It used to be called the "head tax" registers, which you can learn more about on the Vancouver Public Library Chinese-Canadian Genealogy guide, also found in the Resources below.
Resources
Databases
Immigrants from China, 1885-1949
Microfilms
General registers of Chinese immigration
The (unindexed) microfilm reels of the General Registers of Chinese Immigration, 1885-1949 (Reels #C-9510, #C-9511, #C-9512, #C-9513), found in the Library and Archives Canada.