The WRF-ARW and WRFDA v3.8 were used to assimilate AMSR2 (Advanced Microwave AMSR2 Scanning Radiometer 2) satellite microwave imaging data under cloudy and rainy condition, and to examine its influence on the forecast of a typhoon called "Wimason" (No.9 in 2014). Results show that:(1) The pixels reserved by the quality control scheme under cloudy and rainy condition are significantly more than these the quality control scheme under clear sky. The simulation results of brightness temperature is closer to observation. (2) After adding the influence of cloudy and rainy,the simulation results of wind field, height field and sea surface pressure are better than those in clear sky, on the other hand, the influence of cloudy and rainy also increases temperature and humidity of Typhoon center. (3) Both the path and intensity of typhoon forecast are improved by the simulation under cloudy and rainy condition.