Abstract: The dyeing and finishing properties and processing technique of the copolymerized fiber made of wool regenerated protein and polyacrylonitrile were studied.The fiber was considered to have specific problems in bleaching and dyeing.The process conditions of the pretreatment with ferrous ion and of bleaching with H2O2were determined,and the whiteness obtained was up to the requirement.A new idea was brought out,that is,to make a new type of mixed dyestuff designed specially for the dyeing of this fiber.The special dyestuff for the fiber was prepared by first mixing cationic dye with anti-precipitator at the ratio of 1∶7-9(by weight) which was determined by employing conductometric method,then mixing with acid dye.This has provided a theoretic reference for dyestuff exploitation of this new type of fiber or similar fibers and fir dyeing and finishing thereof.