Abstract: A new invariants classification feature based on cyclic temporary cumulant is proposed for classification of MPSK signals. The new feature only uses the symbol rate information, which is resistant to shaping pulse and invariant with respect to the time-translation, local carrier phase offset and amplitude scale of the baseband MPSK signals, and can suppress stationary additive noise. The signal selectivity of cyclic temporary cumulants makes it possible for the proposed feature to be applied to modulation classification of multi-signals. Theoretial analysis and extensive computer simulations show the efficiency of the proposed classification algorithm.