The noise will be introduced to the thenar palmprint image acquisition process. A method which not only bears good denoising effect，but also can enhance the ridge information is required. The principles and specific implementation methods of Pulse Coupled Neural Network(PCNN) filtering and intermediary filtering are put forward. According to the principle analysis for these two filtering algorithms, it is pointed out that these two filtering methods can meet above requirements. Simulation results show that intermediary filtering can process images more clearly and protect image details better than other methods; furthermore，the Peak Signal to Noise Ratio(PSNR) metric data also proves the effectiveness of these two methods.