Based on T639 (0.28125°×0.28125°) global grid data, the snowstorm process during 9-11 November 2009 in North China was simulated by WRF model. The results indicate that precipitation belt distribution in this process can be simulated well by WRF model. Diagnoses of the output data show that the vapor transported by the 700 hPa southwest jet flow made a humidity province in North China and prepared sufficient moist conditions for the snowstorm; the convergence of low level air flows and the divergence of upper air flows result in the strengthening of ascending motion and the genesis and maintenance of the center of low level positive vorticity, therefore the water vapor condensation in the vertical direction is the genesis mechanism of the snowstorm. Based on the CloudSat satellite data downloaded, the shape of ice water content distribution simulated in middle latitudes (39.9°N,117.3°E-33.7°N,115.5°E) is similar to ice water content of CloudSat, but in lower latitudes （30.6°N,114.6°E-24.2°N,112.7°E） the model simulated nothing.