The paper introduces the summary about WRF (Weather Research and Forecast) which is a middle scale model,and analyses the model's physical frame.Furthermore,the numerical simulation ,which is about the wind speed and temperature field in the winter atmospheric boundary layer of Lanzhou city which lies in the hollow terrain,is carried out by using WRF .The result of simulation is nearly in accordance with the observation fact.It indicates that the WRF model has favorable steadiness.