The invention discloses a through-feed polishing system which comprises a conveying line, a fixed frame, a lifting component, a polishing component and a PLC, wherein the conveying line is used for conveying a workpiece; the fixed bracket strides over the conveying line; the lifting component is mounted on the fixed frame; the polishing component is mounted on the lifting component; and the PLC controls the lifting component to perform lifting motion to drive the polishing component to be contacted with the workpiece to perform polishing or resetting. The through-feed polishing system can increase the workpiece polishing efficiency and meanwhile guarantees the polishing quality.