Abstract: PM_2.5 samples were collected at Tangshan in four representative sites during July 2012,which were Tangshan Industrial Zone(iron and steel metallurgy industry),Fengnan(economic development zone),Tangshan Monitoring Center(residential and commercial mixed area) and the Tangshan University City(cultural and educational area). PM_2.5 characteristics were studied through the analysis of elements and water soluble components,and the source of PM_2.5 was analyzed by positive matrix factorization(PMF). The results showed that average concentration of PM_2.5 was 97 μg/m³. The concentration order was as follow: Industrial Zone > Economic Development Zone > University City > residential area. Fe,Pb,Mn enrichment factors in Industrial Zone and Economic Development Zone were also significantly higher than other regions. University City was influenced by the surrounding construction activities,and the concentration of Al was the highest. Secondary inorganic aerosols accounted for 47. 7% of the components of PM_2.5 . The fixed source and mobile source contributions were also different according to different sites.High temperature and humidity were good for generating secondary inorganic aerosols; SO₂ conversion rate was0. 57,and NO₂ conversion rate was 0. 39. The major sources of PM_2.5 were metal metallurgical industry,unorganized dust,motor vehicles,cement,ceramic industry,and the regional transmission also contributed to PM_2.5 pollution.