Abstract: Three experiments of emission sources cutting down were carried out to find out the best way for controlling the photochemical pollution by using the coupling model of MM 5 and RADM. The results show that when the ratio of NMHC/NOx is large, the cutting down of surface NOx source emission is the most efficient way to decrease O3 in atmosphere while the cutting down of NMHC is most efficient way to decrease PAN in atmosphere, and cutting down of NMHC and NOx at the same time is best way to control the atmospheric photochemical pollution.