Currently both RTTOV and CRTM have been used in the WRF data assimilation (DA) system for radiance assimilation under all-sky weathers. To well know the influence of both fast radiative transfer models on radiance, GPM/GMI is assimilated in WRFDA system for one storm case occurred on July 19-21, 2016, in Beijing, China，then compare the simulated brightness temperatures to their observed equivalents in this work. The comparisons show that at GMI low frequencies(10-23 GHz) the simulated Tbs from RTTOV seems better than those from CRTM due to using emissivity atlas in RTTOV since the low frequency channels are more sensitive to the land surface. For rainy pixels over land, both simulations for GMI mid-high frequency channels are significantly affected by the cloud and precipitation. For GMI 5-9 channel, the simulated Tbs from RTTOV is more consistent with the observations than those from CRTM which is dramatically lower than both the observations and the simulated Tb from RTTOV when observed Tb is lower than 260 K. For GMI channel 10-13, both simulations are quite close but far away from the observations. In a word, for GMI 1-7 channels, simulated Tbs from RTTOV are much close to the observations, while for GMI high frequency, such as higher than 89GHz, both RTTOV and CRTM still need more improved in rainy condition.