Based on the air pollution index data from December 2003 to December 2013, the variation characteristics of air pollution in Yueyang, and the actual weather, largescale circulation backgrounds, and causes of typical air pollution processes in 2013 in Yueyang are analyzed. The results show that API index reduced significantly in Yueyang in recent 10 years. The air pollution in winter was the most serious with big annual change, and relatively light and small in summer with small annual change. API index showed a Vshaped change from January to December, and monthly average API was higher in winter (from October to next March) and lower in summer (April to September). The time and space distribution of air quality in Yueyang was influenced significantly by the industrial layout, dominant wind direction, and geographical conditions. The atmosphere in a stable condition, such as great diurnal range and temperature inversion, aggravated air pollution. Local meteorological and nonlocal input factors resulted in the typical air pollution process over Yueyang in 2013. Using the multiple regression method to establish the API index forecast equation, the results show that meteorological elements and weather phenomenon in Yueyang had a significant influence on API index.