Abstract: In order to reveal the developmental mechanism of fog in Qingyang, and further improve the forecast accuracy of fog, using the fog data of Qingyang City from 2007 to 2013, the author analyzed its climate characteristics and influencing factors. The results were as follows: the fog in Qingyang was mostly caused by backflow, and mostly occurred in Ningxian of southeastern Qingyang, the optimum season for fog occurrence was summer and autumn, mainly from July to November. Qingyang’s fog had the characteristics of continuity, sustainability, and was more local and less regional. The time of the fog’s occurrence and lift in spring and summer was different from those in autumn and winter. Humidity was the decisive factor, the temperature and fog had weakly negative correlation. Fog occurred on the ground by weak south wind (wind speed≤4 m/s), and had a certain vertical wind shear. On the ground form field, Qingyang’s fog occurred in a stable, weak or degenerative high-pressure situation, so it had the characteristic of plateau slope backflow fog.