The reasons, radar image products features and radar inversed physical quantity of a rainstorm in the central Jiangsu on 12 July, 2010 are diagnostically analyzed and quantitatively estimated. Results show that the wind field divergence feature reflected by the radar radial velocity helps understand the rain tendency. The divergence data extracted from the Doppler radar radial velocity and from NCEP tended to be consistent, but differences existed in position and intensity between convergence and divergence. The radar inversion divergence intensity is 4-5 times stronger than the NCEP one. Both of the two divergences during the adjustment of vertical height field configuration can reflect precipitation dynamic field change of the heavy rainstorm. The average divergence inversed below 400 hPa is more reliable, especially for the precipitation process whose rainfall rate was lower than 16 mm/h. The average divergence and vertical velocity characteristics calculated quantitatively by the radar base data turned to change with time and height, which reflected the dynamics characteristics of strong rainfall process;the frequent lightning appeared 1-2h ahead of the rainstorm occurrence, and the evolution of lightning with time was consistent with the temporal and spatial distribution of radar echo intensity, so that it is feasible to describe the lightning growth by E_kin, and there were 40 mins approximately before rainfall, which helped forecast rainfall.