Abstract: This research is focused on Doppler velocity ayalysis of a heavy rain process,which was closely observed by Xiamen 714SD Doppler radar——the first one made in China.The process consisted of two heavy rainfall.The first one was caused by a low level shear line that invaded high energy area.When the first heavy rainfall occurred there were three air streams at the low level.The second one was produced by a cyclonic vortex,which developed along the shear line,and the fluctuation of low level SW jet stream in PBL.Although the two heavy rainfalls differed in mesoscale systems and flow features which accompanied them,there may be some relationship between them.