The invention discloses a polishing device for the inner wall of a tubular workpiece. The polishing device comprises a rack, a drum and a crank and rocker mechanism, wherein the rack is composed of a base and a swinging and rotating frame arranged on the base, and the middle portions of the two sides of the swinging and rotating frame are horizontally supported by two supporting columns extending from the base through lugs; a tubular workpiece clamping opening is formed in the side wall of the drum, and the outer side of the clamping opening is provided with an arc pressing cover which covers the clamping opening; a charging opening with a sealing cap is arranged at one end of the drum; the two ends of the drum are supported by the two ends of the swinging and rotating frame through other lugs, and one end of one of the lugs is connected with an output shaft of a first motor arranged outside the swinging and rotating frame. The crank and rocker mechanism is formed by sequentially hinging a crank, a connecting rod and a rocker, wherein the free end of the crank is fixedly connected with an output shaft of a second motor arranged on the base, and the free end of the rocker is fixedly connected with the corresponding lug. The polishing device provided by the invention has the advantages that polishing is uniform, and the structure is simple.