A comparative analysis is made with the application of the Doppler weather radar data of three strong convection precipitations at the night of June 12, in the wee hours and night of July 12, 2006 in Tianjin region. The results show that th e change of the radial velocity field often precedes that of echo intensity f ield of Doppler weather radar during the beginning and mature stage of precipita tion. It indicates that the effort on the shorttime forecast of precipitation should be focused on the change of radial velocity field and also refer to the f oreca st outcome of Autonowcasting system. The accuracy in the shorttime forecast of strong convection precipitation process can be improved through judging the i ntensity change and moving direction of radar echo.