Abstract: In order to understand the spatiotemporal distribution of PM₁₀ over Liaoyang of Liaoning province and provide a scientific basis for air pollution prediction and measure of prevention,the spatiotemporal variations of PM₁₀ were analyzed using daily monitoring data of PM₁₀ in Liaoyang of Liaoning province from 2006 to 2012.The results show that the annual mean PM₁₀ concentration decreases significantly during this period.The PM₁₀ concentration is the largest in winter,followed in spring,autumn,and summer.The monthly mean PM₁₀ concentration exhibits a "U" type distribution,with the higher values in January,February and December and the lowest one in July.The highest PM₁₀ concentration is observed in Yuanlinqu station (a residential area),followed by Gangguanchang station (an industrial area),201 Xuezhan station (a traffic area),and Liaohua station(a clean area).The PM₁₀ concentration has been observed decreasing at all monitoring stations in the recent 7 years,except for the Gangguanchang station.