Abstract: The local VAD method is used for the wind retrieval from radical wind measured by Doppler radar (data from CAMS, at 12:00UTC, 5 July 1998) into horizontal wind and an experiment is made on the impact of horizontal wind on numerical weather prediction assimilation system for the heavy rain occurred from afternoon to night of 5 July 1998 in the Beijing area.The result shows that the retrieved wind is primarily consistent with the weather process and it can be used in the analysis and prediction of mesoscale systems with smaller temporal and spatial scales.