Cyclic spectral correlation above the bifrequency plane for the received signal was calculated by the strip spectral correlation algorithm (SSCA)and then was normalized. The result was expressed by matrix. The sum of error- square was computed between corresponding elements for the theoretical sampling matrix of all kinds of modulated signals and calculated matrix . The modulation type was recognized by exploiting the minimum value of the sum of error- square . No extracted characteristic parameter and prior information are needed for identifying the modulation type compared to the conventional methods. In addition, the new method extends the recognition scope and has high recognition probability at low SNR . The simulation results obtained by means of Monter- Carlo method proved the presented algorithm.