With the study method of using remote sensing technology combined with measuring the air temperature and using 1987~2001 remote sensing image data,the urban green space subject map and heat island distribution map of several years have been established with some analyses of the changing characteristic of urban green space and heat island effect in Beijing among the 13 years,and the effect of urban developing and urban greening on heat island.The result indicated that be influenced by urbanization,the urban green space and the urban heat island changed greatly.With the urban building range increasing continuously,the area of original natural vegetation decreased,the scope of urban heat island extended;with the urban greening developing,the total quantity of green space increased,and the urban heat island effect attenuated gradually.