Based on the data from the South China field observation experiment in summer 2023, the contribution of assimilating Beidou sounding data from the Guangdong network to the forecast of Typhoon Saola (No.2309) is analyzed by means of the three-dimensional variational assimilation method of the Weather Research and Forecasting Model (WRF) and its variational assimilation system (WRFDA). The application prospects of the fully operationalized new Beidou sounding observation system are also explored. The study reveals that Beidou sounding has basically the same quality as L-band sounding at the same station, and as ERA5 reanalysis data and FNL analysis field data, so it has high observational value. The effective assimilation of Beidou sounding data can adjust the temperature, humidity, and wind fields of the background field to varying degrees, significantly improving the quality of analysis field, and also has corresponding improvements in the forecast of the typhoon’s track, intensity, and precipitation forecast. Among them, the track RMSE is reduced by 11.87% compared to the non-assimilated Beidou sounding.