The vertical distribution characteristics of a dust and fine particle pollution process of Nanjing were measured and studied by polarization lidar in March, 2015. The meteorological factors, particle concentration distribution, particle composition and optical properties of different kinds of particles were discussed, combining with ground meteorological data, PM2.5 and PM10 concentration data, PM2.5 component data and the result observed by MODIS satellite. The results indicate that the adverse weather conditions such as high humidity and weak wind are favorable for the formation and accumulation of the secondary particles, and the SNA (SO2－4, NO－3, NH+4) concentration of soluble components showed a significant increasing trend during the experimental period. At the same time, the settlements of sand particle from long distance significantly influenced the chemical composition of the ground PM2.5. The dust particles from 1.1 km to 2.5 km were transported to the ground during afternoon of March 21 to March 22, which caused Ca2+ iron concentration of PM2.5 increase to 3.2 μg/m3 suddenly. The PM2.5 spread to the west and the PM2.5 concentration was reduced efficiently under the influence of southeast current after afternoon in March 22. At the same time, dust transport and fugitive dust occurred, causing the concentration of coarse particles up to 347 μg/m3. Compared with the particle distribution of Wuxi, the particle distribution characteristics in Nanjing showed highly similar characteristics, it indicated the particles distribution was regional. Finally the backward trajectory analysis showed that the backward trajectories were largely consistent at the height of 500 m, 800 m and 1000 m, the air mass mainly originated from Mongolia, and passed Beijing, Shandong, then moved to the East China Sea, finally backed to Nanjing.