Abstract: The WRF -3 DVAR system is used to assimilate GPS radio occultation and GPS precipitable water,in order to simulate the heavy rain weather process on June 14th,2011. The results show that: both precipitable water and radio occulta- tion refractivity data in numerical simulation can significantly improve the low levels' water condition of the analysis field. Pre- cipitable water vapor has more impact than radio occultation refractivity, in improving the rainstorm intensity and influence scope. The assimilation of radio occultation refractivity data can expand the storm rainfall area by modifying the wind fields and potential temperature fields. GPS radio occultation refractivity assimilation can supply the precipitable water vapor detection site distribution. Combination of GPS precipitable water and radio occultation assimilation can greatly improve the forecast of rain- belt distribution, intensity, scope and falling area. Both of them can be well complement for each other.