In the process of high-orbit target imaging with intensity correlation method, the low detecting signal to noise ratio and inaccurate phase retrieval algorithm seriously affect the imaging quality. To realize the high-orbit target imaging clearly, the amelioration and optimization of estimation method to spatial spectral modulus and phase retrieval is discussed according to the priori information of spatial spectral distribution of high-orbit satellite, priori information of satellite images and noise distribution characteristics of intensity correlation imaging method, indoor experiment is designed to verify the validation of algorithm. Laboratory experiments indicate that the imaging quality is significantly improved as well as the ambiguous images and noise speckle reduced with improvements and optimization of estimation method of spatial spectral modulus and phase retrieval algorithm.