Abstract: The non-hydrostatic mesoscale model MM5 is used to simulate the winter heat island of Beijing city with three-fold nesting and the finest mesh resolution of 3 km. With the observed building heights and landuse data of a 200 m×200 m resolution in Beijing interpolating into the model, and dividing the urban artificial heat of the underlying surface into two parts (constant and daily-changing parts), the simulation results show that the numerical model can successfully simulate the heat island effect and its circulation. The simulated daily cycle of the heat island is closer to the observation for the daily-changing anthropogenic heat than for constant heat. It indicates that using the heat conforming with the observation in the model can improve the numerical simulation of the heat island.