The key to application of weather radar pulse compression technology is to suppress the distance side lobe after pulse pressure. The generalized cosine window which has a bell shaped feature can effectively smooth spectrum edge, reduce the ratio of main lobe and side lobe, so it is widely applied to linear FM signal pulse pressure side lobe suppression technology. This paper studies about the side lobe suppression using the generalized cosine window as the weighted network, and makes a comparative analysis of their ability to detect weak target. At first, the article briefly describes the pulse compression technology and the main performance indicators of judging side lobe suppression effect and then presents a simulation of the spectral characteristics of the generalized cosine window. Finally, the paper brings the generalized cosine window into the signal processing of the real solid state weather radar, getting the echo images, making a comparison of Doppler weather radar and giving comparative analysis results.