Abstract: In this paper, we propose an approach that can blindly separate the PN sequence and message sequence in weak DS-SS signals. This paper proposes the problem of DS-SS signal blind separation firstly, then analyzes the blind adaptive method of stochastic gradient constant modulus algorithm (CMA) in detail, and applies the CMA to the question of DS-SS signal blind separation in the end. This method is totally different from the existed method, which based on decomposition of matrix. It possesses a lot of advantages. Theoretical analysis and experimental results show that the approach can work well for weak DS-SS signals.