Abstract: Based on the sounding data of 11 observatories in Sichuan Province during the Southwest Vortex Intensive Observation Experiment in 2017, this paper uses the regional 9km and 3km resolution numerical weather prediction model system to carry out numerical prediction assimilation experiments. The assimilation test was performed twice daily for 06 and 18 UTC, and last for 40 days. The simulation results of the 9km resolution numerical forecasting system (SWC-WARMS) show that the observed sounding data complements the upper air observations in Sichuan. After assimilation of intensive data, the initial field of the model can be improved, which helps to improve the ETS score of the 24-hour precipitation forecast, and also improves the BIAS score from light rain to heavy rainfall. Benefits from a higher grid resolution, the 3km resolution numerical forecasting system shows a reduction in the area of heavy rain, compared to SWC-WARMS. The assimilation of sounding data in the 3km resolution system can also improve the ETS score of precipitation forecasting, but the area of false alarm has increased.