Abstract: In this paper, two types of gust fronts are compared by using the weather radar date obtained in Beijing, China and Oklahoma, U. S. A.. The first type is the fast moving gust fronts, which is often accompanied by violently developing storms, the onset of it gives an indication for the continuous development of severe storms. The other is the gust front moved slowly (static gust fronts) which is often occurred at the weakening stage of the relevant storm, the occurrence of it speeds up the end of the storm. The formation of the gust fronts is related to the downdraft in the storm, and the two types of gust fronts are the results of different interactions between downdraft and environment. Also, the cause of formation of the radar echo from the gust fronts has been studied too. It is believed that the radar echo is the result of activity of air turbulence occurred in the boundary between the draft and environment flow. The theoritical estimation of the echo intensity of gust fronts based on the Doppler weather radar data and tower data, is satisfactorily consistent with the observation data