Abstract: Based on the observation data of weather station and ambient air quality monitoring data in Chengdu from 2012 to 2020, the spatial and temporal evolution of visibility and the relationship between meteorological factors and pollutant concentration under different levels of visibility are studied. The results showed that: (1) The average visibility in Chengdu has been increased year by year in recent 9 years. The order of average visibility in four seasons is: summer (12.25 km), spring (10.82 km), autumn (9.04 km), and winter (6.33 km). The diurnal variation of visibility in Chengdu presented a single-peak distribution, with the lowest visibility at 07 am and the highest visibility at 17am. (2) The spatial distribution characteristics of visibility were high in the east and low in the west, high in the north and low in the south, with the lowest visibility in the central urban area. (3) The occurrence frequency of low visibility below 3 km was 10.92%, and the frequency of visibility below 3~5 km, 5~10 km and 10~20 km was 15.92%, 24.95% and 22.51%, respectively. (4) The increase of visibility was related to the corresponding PM2.5 and PM10 concentrations, the decrease of relative humidity and the increase of wind speed. When visibility is less than 1 km, the environment is usually characterized by high humidity (RH>96%), low temperature (T<10.6℃), low wind speed (<1.0m/s) and high pollutant concentration (PM2.5>84.8 μg/m³, PM10>129.0 μg/m³).