Abstract: To investigate how the assimilation of the data from the microwave humidity sensors(MWHS and MWHS2)on-board the FY-3B and FY-3C impacts the numerical prediction of thunderstorm cases in Sichuan basin,this paper focuses on using the Weather Research and Forecasting(WRF)model and its 3D variational data assimilation system(WRFDA)to direct assimilate of the MWHS/FY-3B and MWHS-2/FY3C observations.A case study of the assimilating experiments of a regional thunderstorm process in Sichuan basin in July 2018 shows that the assimilation of FY 3-series MHWS observations(a)improves the initial fields of the experiments, (b)positively adjusts the relative humidity field,wind vector field,and other physical quantity fields,and(c)particularly regulates the wind field by assimilating the MWHS-2/FY-3C data.The assimilation improves the precipitation distribution in the northern Mt.Longmeng and the assimilation of MWHS/FY-3B improves the precipitation forecast to the observation in the mid-eastern Basin.The experiments of this case study have showed the operational value of the assimilation of the FY 3-series MWHS data in the numerical prediction of the thunderstorm cases in Sichuan basin.