Based on TRMM 3B42precipitation data, 5time series at annual scale were defined. Then the spatial and temporal dynamics of rainstorm were evaluated by GIS technology and mathematical method. The results show that Both the amount of annual precipitation and annual rainstorm precipitation appeared slight decrease trend and their spatial patterns were much similar in the past 13years. Significant fluctuations of rainstorm ratio could be found in the past 13years. In the rainstorm concentration area, annual rainstorm precipitation shows more significant fluctuations than annual precipitation. Annual rainstorm frequency changes smoothly but with significant spatial difference. The imbalanced distribution of rainstorm in latitudinal direction is more obvious than that of longitudinal direction. Rainstorm showed tendency of moving to northeast in the past 13years. The changing trends of the five variables show significant spatial differences and most areas appear increase or decrease but not significant trend.