In order to research the problems which optical correlator can not recognize with the rotating target. It is proposed that by using the plane mirror group we can obtain the target image and recognize with the mirror image of the template image. In the optical system of acquire target, inserting a polygonal prism which is enclosed by plurality of plane mirror, it can make the target to produce a set of different angles mirror image. The similar angle mirror image can be found from a set of mirror image by different rotation angle target, and correlation peak is acquired when such target image and template are correlated. Experimental results show that mirror image of the rotating target obtained by the plane mirror group as the target image, is an effective way to resolve problem that optical correlator recognize with the target.