Firstly, this paper describes the significance of research on modulation identification techniques in communication countermeasure, the single carrier and multicarrier communication modulation system, the smart communication countermeasure. Then, it introduces the actuality of research on modulation identification about wireless digital communication. For making a good foundation for the smart communication, it is very necessary to realize the signal features’ interclass and intraclass identification well in the single carrier and multicarrier modulation system. This paper proposes a new algorithm for modulation identification about the single carrier and multicarrier. The algorithm is able to complete the signal features’ modulation identification over the timevarying Rayleigh channel between OFDM and MPSK. Simulation results demonstrate an over 90% correct classification rate could be reached when the SNR is above 7dB.