The invention relates to a polishing device for an alloy pipeline. The polishing device comprises a base, a fixing rod, a cross rod, a driving mechanism, a polishing mechanism, a fixing mechanism anda cleaning mechanism, the driving mechanism comprises a motor, a driving shaft, a walking ring and a first lead screw, and the fixing mechanism comprises a first fixing plate, a second fixing plate and a second lead screw; and the cleaning mechanism comprises a first water tank, a second water tank, a connecting pipe, a water inlet pipe, a water pump and a water outlet pipe. According to the polishing device for the alloy pipeline, polishing of the inner wall of the alloy pipeline is achieved through the polishing mechanism, and uniform polishing of the inner wall of the alloy pipeline is achieved through a polishing block in a rotating manner, so that the polishing effect is improved, and a polished product is more attractive; the alloy pipeline is fixed through the fixing mechanism, so that the inner wall of the alloy pipeline is vacuumized; and polished dust is cleaned through the cleaning mechanism, so that the situation that air pollution and harm to an operator are caused due todust suppression is prevented, and intelligent polishing of the alloy pipeline is achieved.