Abstract: An one-dimensional atmopheric chemical model is developed. Using the model, diurnal variations of ozone and other trace gases have been simulated, and several sensitive experiments have been made. The results show that increments of CH4 or CO cause O3 to increase and increment of water vapour causes O3 to decrease; in the free atmosphere O3 decreases with a rise in temperature, but in the boundary layer O3 increases; when solar radiation enhances, O3 decreases in the free atmosphere, but in the boundary layer O3 increases. In addition, the influence of the boundary layer on the distribution of trace gases is studied. It is found that the effect of the boundary layer has to be considered in the simulations for the variation of trace gases in the lower atmosphere