The paper compared and analyzed the effect of meteorological conditions from the aspect of atmospheric circulation background and pollution evolution of two air pollution processes in Guiyang based on the Air Quality Index (AQI), precipitation and atmospheric circulation field. The results show that both dynamic and thermal meteorological factors provided favorable conditions for maintenance and development of the two pollution processes. However, there were similarities and differences. The similarities were that Guiyang was located behind the ground stationary front in the two pollution processes where the surface wind speed was small, which wasn’t in favor of the horizontal conveying of air pollutants near the surface. Guiyang was located in the anomalous downdraft region in front of the high ridge, with the decrease of the anomalous vertical wind shear in the middle and lower troposphere, the atmospheric baroclinicity reduced and the synoptic scale disturbance weakend. The presence of anomalous inversion layer made the atmospheric stratification more stable near the surface layer. All of the above were not conducive to the vertical mixing and the high-altitude diffusion and enhanced the accumulation of pollutants near the ground. The differences were that there were different degrees of single and double inversion layers over Guiyang during the two pollution processes. The inversion enhancement period corresponded to the most polluted period. The inversion layer greatly enhanced the stability of atmospheric stratification and provided favorable meteorological conditions for the maintenance and development of the pollution processes. The wind field had different effects on the inversion layer during the two pollution processes. In the first pollution process, the southerly wind in the middle troposphere was beneficial to transporting warm and moist airflow from the south, which was conductive to the development of warming and humidifying of the inversion layer over Guiyang city. In the second pollution process, the northerly wind at high and low troposphere was easily to form cold air cushion and raise the warm air, so as to strengthen the maintenance and development of the inversion layers.