The weather Doppler Radar(CINRAD/SA) is of various application and powerful functions. With the observation data of Doppler Radar at Wenzhou,the intensity of radar echo and Doppler velocity about Typhoon Rananim ect.,as well as their variation are analyzed,the features of radar echo and velocity are revealed. The facts are as follow: the smaller the Typhoon eye is, the stronger the typhoon is, the stronger the convection is. There are spiral rain belts and close structure in the strong typhoon. The typhoon heavy rain is connected with convergence upward of cyclone vorticity. The strongest heavy rain distributed in the right head of typhoon track. Because of the impacts of topography, there is very different precipitation even though the vertically integrated liquid water in the same. In the coastal area, it is very important that the typhoon variation is detected by Doppler radar.