The rainstorm in Anhui Province on July 13th,2001 is simulated by numerical model ARPS(Advanced regional prediction system) and its 3D-VAR(3-dimensional variational data assimilation) system developed by CAPS(Center for analysis and prediction of storm) and Doppler radar data in China.Assimilation experiments are carried on by adding Doppler radar data at 10 and 30 minutes intervals,respectively,with the former results as the followed one’s initial fields adjusted continuously.It is found that the winds and water vapor fields are obviously improved after inducing Doppler radar data,especially the 3-h precipitation simulations.And more times radar data induced,better the forecast simulations.