Abstract: In this paper，correlation coefficient of envelope on specific emitter recognition is discussed when the received radar signal is a normal type. In this approach, in order to determine which specific radar generated the intercepted signals belong to the same kind after classified , received signals are firstly filtered by DFT to reduce the noise ,then the envelope of the processed signals are extracted. Computer simulation results show that the method is able to identify the two specific radar emitters with an accuracy rate of 96％ when the correlation is about 0.99, and the input SNR is 0 dB.