Abstract: An automatic recognition algorithm of digital modulation signals in satellite communication is presented,which connects high order cumulants with constellation characters.It is invariant with respect to difference of amplitude and phase,and it can suppresses white additive Gaussian noise.Compared with the existing algorithms,it is robust and widely usable.Computer simulations show that application of this algorithm in a medium signal-to-noise ratio with a specified sample size results in the high probability of correct identification(>95%).