Abstract: The diurnal variation of ozone and NOx in marine atmospheric boundary layer was studied by atmospheric chemical model MECCA,with the modeling results compared with the observed data.Halogen(Br,Cl and I) chemical processes were considered in this model.When the influence of halogen chemical processes was included in the model,a decrease of ozone concentrations and time advance of the peak concentration of ozone are revealed.The main reason is that the reactive halogen radicals such as Br,BrO,Cl and ClO show peaks after sunrise.As the same reason,the NO2 has the same change tendency with ozone.In clean environment,ozone destruction rate in marine atmospheric boundary layer was mainly controlled by HOx, O(()¹D)+H₂O and halogen species,and during the daytime,the ozone destruction was mainly derived from reactive halogen species.The impact of variation of initial NOx concentration on ozone concentration was also studied.In high NOx situation,there is a net production of ozone in marine atmospheric boundary layer.