Aiming at shortcoming of classic joint transform correlator,a joint transform correlator based on chirp modulation and slantwise parallel wave illumination the power spectrum was presented,which resultsed in enhanced correlation peaks with chirp modulation of input image and centralizing relative correlation peaks by slantwise parallel wave illumination the power spectrum.The method did not need digital process with computer and was real-time.The theoretical analysis and experiment results show that better peaks and only one relative correlation peak on the detector are obtained,which improve greatly recognition ability and make use of detector and input plane.