Abstract: Reserch on the performance of BeiDou satellite navigation system in retrieving atmospheric precipitable water is conducive to promoting the application of BeiDou in numerical weather forecasting and meteorology research. Based on BeiDou final precise ephemeris (WUM) products, rapid ephemeris products (WHR) and ultra rapid ephemeris (WHU) products released by  Wuhan University, Using GNSS multimode observation data provided by MGEX station and single CORS station, after verifying that the accuracy of tropospheric zenith delay calculated by the three BeiDou precise ephemeris products meets the requirements, the atmospheric precipitable water vapor calculated by the three BeiDou precise ephemeris products is compared with GPS water vapor detection results, ERA-5 reanalysis data and sounding station data respectively, and the BeiDou water vapor detection performance based on the three precise ephemeris products is analyzed.The experimental results show that the precision of atmospheric water vapor detection based on BeiDou final precise ephemeris products is higher than that of fast ephemeris products and ultra rapid ephemeris products, and the relative accuracy and reliability of atmospheric precipitation inversion of the three kinds of BeiDou ephemeris products are equivalent to that of GPS, which meets the requirements of small and medium scale numerical weather forecasting and meteorology research.