In order to solve the current image matching algorithm in identifying goals, rotation, scaling workpiece has the problem of matching positioning success rate is not high, is proposed in this paper based on the analysis and moment invariant features of rotary workpiece contour matching algorithm. First of all, using the adaptive binarization of image preprocessing, and traverse the image contour, contour sequence was extracted and area computation, realize to rule out the impurity interference. Then by calculating image moment invariant features of contour sequence, establish function matching degree, compared with template target moment invariant features, complete the rotating zoom workpiece target matching. Test results show that compared with the current image matching algorithm, the target is zoom, rotate interference, in this paper, matching algorithm has a higher success rate.