Aiming at the crosstalk and noise problems of wireless optical signal transmission in space laser communication, combined with constant modulus algorithm (CMA) and least mean square (LMS) algorithm, a two-stage cascade variable step size adaptive equalization algorithm——CMA-LMS equalization algorithm is proposed, the size of the step factor has a nonlinear relationship with the theory in a certain range. The product of the theoretical data and the step factor is used to update the algorithm variables to achieve the nonlinear adaptive equalization of the channel. The experimental results show that the CMA-LMS equalization algorithm can improve the performance of the system, and under 16 quadracture amplitude modulation (16QAM), CMA-LMS equalization algorithm can effectively suppress the noise and crosstalk of the system.