Herein Doppler radar reflectivity and radial velocity data assimilation experime nts are carried by means of ARPS ADAS (ARPS Data Analysis System) and 3Dvar (3 D Variation System) respectively. Roles played by ADAS and 3Dvar in improving in itial fields and forecast results are analyzed. Through investi gating one rainstorm process occurred in Anhui Province, July 2003, it indicates that radial velocity data affects initial wind field, along with integral begin ning, water vapor field is adjusted too. Reflectivity data impacts initial water vapor field, and after integration, the wind field is improved. The effect of r eflectivity is more evident than that of radial velocity. Moreover, for the 3h r ainfall simulation, reflectivity and radial velocity assimilation experiments ar e both different with observations in situ, the former one is greater than the o bservation. While the both results of assimilation experiments are better than t hose of the nonassimilation ones.