The invention discloses an opener for purified cotton. Upper and lower rollers are arranged at a feeding hole, and various taker-in rollers are arranged inside a shell; a connecting line of centers of the taker-in rollers is on the same inclined straight line, and intervals between the centers of adjacent taker-in rollers are the same; an inner roller is arranged on the shell among the taker-in rollers; a main conveyer belt is backward and upward arranged at the front end of the feeding hole in an inclined manner; an inner conveyer belt is backward and upward arranged in the shell at the lower end of the taker-in rollers in an inclined manner, the interval between the inner conveyer belt and the lower end of the taker-in roller close to the feeding hole is less than a ratio, namely one to the number of the taker-in rollers, of the whole thickness of a cotton bag, and the rear end face of the inner conveyer belt is close to and slightly higher than the lower end of the taker-in roller at the feeding hole; a negative pressure cotton discharging region is kept between the taker-in rollers and the upper wall of the shell; and a conveyor motor supplies power to the main conveyor belt, the inner conveyer belt, the upper and lower rollers and the inner roller, and a main motor supplies power to the taker-in rollers. The opener for the purified cotton has the advantages that the cotton bag does not need to be manually broken up into multiple layers, continuous feeding can be realized, the energy consumption is low, the production efficiency is high, the yield is high, and opened cotton blocks are small.