Abstract: In order to study the radar data assimilation effect on Anhui rainstorm forecast, the author used WRFV3.4 mode to simulate a heavy rainfall from July 12 to July 14, 2012 in Anhui Province, selected the combination of Eta microphysical scheme and GD cumulus parameterization scheme, and used the three-dimensional variational assimilation system of WRFVAR3.4 to carry out the direct assimilation test with radar radial velocity data. Comparing precipitation of assimilation experiment and control experiment with actual rainfall, it was found that assimilation radar radial velocity could significantly improve the precipitation forecast in a certain period. Especially in the earlier 6 h, assimilation experiment had significant improvement than control experiment in three grades which were light rain, moderate rain and heavy rain, and after joining Doppler radar data assimilation, wind field convergence characteristics in rainfall area was more apparent, wind speed also had certain enhancement, rainfall intensity and center were closer to actual values. During 12 h after assimilation radar radial velocity data, it was found that the advantage of assimilation test was not obvious gradually.