Pollutants enter into the atmospheric boundary layer (ABL) after emitted from surface sources, which has a great influence on the health of human beings. The diffusion of the pollutants within the ABL is strongly affected by meteorological conditions, such as the radiation, wind speed and turbulent mixing. In order to estimate the effects caused by different meteorological factors on the diffusion, in this study, finite difference method was used to solve the diffusion equation of pollutant. The solution was first compared with the theoretical solution, in order to verify the correctness of the model. Moreover, the model was extended to three dimensions, by considering the vertical mixing between different vertical layers. In this study, we obtained the spatial and temporal evolution of pollutants under different wind speed conditions for different types of pollutant source distribution, which is of guiding significance for the planning and locating of industrial zones in cities.