Surface observation, CMA PM2.5 concentration, Lband sounding second data and other information are used to analyze surface wind characteristics and mass concentration of PM2.5 on fog，haze and clear days in Beijing, Shijiazhuang and Taiyuan from January to February 2013. Typical foghaze processes are selected to analyze vertical structure of boundary layer and inversion layer characteristics, which are also compared with those of clear days. Dynamical and thermal differences in boundary layer are summarized according to different intensities in foghaze processes. Analysis result shows that inversion intensity has a negative correlation with visibility, which has some indicating importance in fog and haze predictions.