This study retrieves the aerosol extinction coefficient, the height of the boundary layer, and the mass concentration of ozone based on differential absorption lidar. Through the atmospheric temperature profile, ground meteorological elements, and air quality data, backward trajectory and naval aerosol analysis and prediction system, a heavy pollution process in Wangdu County is analyzed. Experiment results show that during the observation period, Wangdu County is under the control of the East Asian trough system, and there is always a temperature inversion layer within 100?200 m of the surface layer. When particulate pollution is severe, the relative humidity on the ground is high, the wind speed is low, and there is a weak downdraft at high altitude, which is conducive to the moisture absorption growth and long-term accumulation of particles. The boundary layer height is always low, which is not conducive to the diffusion of pollutants. In addition, the boundary layer height has no obvious correlation with the particle mass concentration, but it is negatively correlated with visibility, and the correlation coefficient is -0.344. The mass concentration of ozone is positively correlated with temperature and visibility and negatively correlated with relative humidity, boundary layer height, and wind speed. The local quiet and stable weather and the transmission of pollution sources from other places are the major causes of air pollution in Wangdu County.