Abstract: In order to solve the problem that parallel robot can not identify specific workpiece in the sorting process and the sorting accuracy is low, a workpiece recognition and positioning technology based on machine vision is proposed. The image of the workpiece is collected by the HK industrial camera, a suitable method is proposed to extract the image edge and then extract the contour of the workpiece. The Hu moment feature of the workpiece contour in the image to be recognized was extracted and the Hu moment feature of the workpiece template contour was extracted for similarity measurement to identify the workpiece. Then the center of mass is extracted and the pose of the workpiece is determined to locate the workpiece. Experimental results show that this method can identify and locate the workpiece effectively, and provides a reference for the identification of the workpiece.