Ground clutter filter is very important in weather radar signal process. Ground clutter will generate strong echo that looks like weather signal, which will disturb weather forecast. The paper introduces the feature of weather signal and ground clutter，analyzes the ground clutter filter used in CINRAD/SA radar now. An adaptive frequency domain ground clutter filter algorithm is proposed based on Gaussian model. The results of two filters are compared based on real radar base data from Tianjin radar site，which show that the new algorithm can effectively remove normal ground clutter and anomalous propagation, and restore weather signal from clutter as much as possible.