An artillery precipitation enhancement operation of hail clouds at the Wuqing district in Tianjin on 2 August 2000 is analyzed in detail by use of WSR-81S Radar data at Tianjin and the corresponding surface precipitation data. The surface rain observation data after the operation shows that there is a large precipitation center in the upstream of the operating site, which means that the operation changed the original distribution of natural precipitation, increased the rainfall in parts of the area. Analysis of the WSR81S radar data shows that during the repeated operations, the radar echo intensity, altitude, and speed decreased; the operation was directed at the movement of the hail clouds，resulting in more precipitation in the upstream area, so the over 45 dBz echo zone remained there.