In January 2019, the moderate to severe pollution process occurred in Tongren, this paper based on the time-by-time environmental monitoring data,high-altitude and ground meteorological observation data in urban areas of Tongren,the meteorological condition characteristics of the pollution process in Tongren was analyzed. The results showed that the primary pollutant was fine particulate matter (PM2.5). When the pollution weather occurs, the sky over Tongren is a high-pressure ridge or a consistent southwest air flow, the ground is cold high-pressure or average pressure zone control, the air pressure gradient is small, the wind speed is small, when converted to high-altitude trough, the ground has cold air supplement, air pressure gradient increased, the concentration of pollutants is reduced. At the same time, the wind speed related to the relative humidity and the concentration of pollutants , when the ground wind speed is small and the air is dry, the concentration of pollutants increased;On the contrary, the wind speed increases to more than 4m/s, and the relative humidity of the air increases to more than 90%. Especially when there is obvious rain and snow, the concentration of pollutants decreases rapidly. In addition, the pollution weather is accompanied by the continuous influence of the inversion layer of the near strata, the thicker the thickness of inversion layer , and the stronger the intensity of inversion layer, inhibits the vertical direction of the atmosphere turbulence exchange, is conducive to the cumulative growth of pollutant concentration. By the terrain of Mount Fanjing blocking, when the near formation is affected by the weak easterly wind, pollutants can not cross Mount Fanjing to the west, will accumulate on the east side of Mount Fanjing, resulting in the accumulation of pollutants in the local circulation of urban areas in Tongren, pollution concentration to maintain a large value. The above results can provide a new reference for air quality forecasting and pollution prevention and control in Tongren.