WRF model system is a new generation mesoscal numerical weather forecast model and data assimilation system which is made by meteorological community of U.S.A. 3DAR and WRF V.20 will be released this year. There are highly modular,transportable,and efficient in massively Parallel Computing environment,numerous physics options in the model,advanced data assimilation system developed in tandem with the model itself. The simulations and real-time forecasting show that WFR model has good property for forecasting many kind of weather. The WRF model fully coupled “online" chemistry,therefore WRF model system has broad application not only in weather forecasts,but also in air quality forecasts.