Abstract: To further study the development mechanism and effect system of fog in eastern Gansu, based on ground data and high and low level data of radiation fog from 2007 to 2013 in Qingyang, we analyzed its spatial and temporal distribution characteristics, climate background and influence system. The results showed that: the fog in Qingyang occurred mainly in central and southern mountain areas, particularly in Ningxian; the fog occurred mostly in February and July to November, and highest occurrence rate was found in October. The high altitude situation of the fog happened at 20:00 the day before and at 08:00 of the day was mainly as follows: trough transit type, trough before type, northwest airflow, ridge before type, and straight flow type; the ground systems were modified classes after high-pressure area, high-pressure area control, low-pressure area control before cold front, saddle type field type and uniform pressure field type. Regional fog was radiation fog, highpressure area rear type fog occurred most frequently, and occurred in each season; then was high-pressure area control fog, which tended to occur in autumn and winter; fog before the cold front and fog of low pressure control were less than fog of high pressure control, and developed in late winter and spring, most frequently in March; fog of saddle field type and uniform pressure field type occurred in September to October, and the occurrences were less. The study reveals the development mechanism of fog in Qingyang, and provides references for fog forecast to reduce industrial and agricultural production damage caused by foggy weather.