Abstract: The urban heat island(UHI)can greatly reduce the comfort of the people who live in cities. Due to the regional weather and complicated surface conditions,the UHI can appear in cities,which can be affected by the human act ivities.The UHI in Beijing is remarkable,and its averaged intensity is about. eduring the period 1960-2000. The present research is done about the numerical simulation of the heat island in Beijing,and focuses on investigating wind and temperature fields near surface which are influenced by various land surface conditions.And the various urban canopies can affect the UHI to certain extent. A regional numerical model,MM5,is employed in this research. The simulation results show that the MM5 model success-fully simulates the heat island effect on Beijing. Comparing the MM5 with the coupled model of MM5 and Noah LSM,the results show the MM5-Noah LSM coupled model does a better job.