The characteristics of PM_2.5 in 13 cities before, during, and after APEC period were analyzed, and the sources of PM_2.5 using the chemical components of PM_2.5 were identified. The results show that the concentrations of PM_2.5 decrease by 58.7%, 52.9%, 50.1%, 47.3%, 43.5%, 36.7%, 34.9%, 33.4%, 29.6%, 26.9%, 20.2%, 19.9%, and 12.8% in Beijing, Shijiazhuang, Chengde, Langfang, Xingtai, Zhangjiakou, Handan, Tangshan, Tianjin, Hengshui, Cangzhou, Qinhuangdao, and Baoding during APEC period, respectively, compared with before APEC period. The concentrations of PM_2.5 decreased on average 35.9%, which is higher than 17.5% of SO₂, 21.3% of NO₂, and 22.0% of CO. The concentrations of NO₃^-, SO₄^2- and NH₄⁺ decreased by 32.0%, 32.9% and 39.1%, respectively, compared with the APEC period. There is no notable difference for the PM_2.5 sources before and during APEC period. The source contributions of coal/biomass combustion, metal smelting, and oil combustion increased to 21.7%, 14.0% and 20.8%, meanwhile, the source contributions of dust, industry, and secondary source decreased to 12.6%, 11.8% and 19.2%, respectively.