Abstract: A total of 48 sets of PM_2.5 samples of atmospheric fine particles were collected indoors during the winter of 2016 in two villages of Xuanwei City, Yunnan Province. The mass concentrations of PM_2.5 were obtained by weighing. Eight kinds of water-soluble inorganic ions, including Na ⁺, NH^+_4, K ⁺, Mg ²⁺, Ca ²⁺, Cl ^-, NO^-_3 and SO^2-_4, were analyzed by ion chromatography. The results showed that the daily average concentrations of PM_2.5 in old coal-fired households in Xuanwei ranged from 52.5 to 417.0 μg/m ³ and those in new electrical households ranged from 43.6 to 77.9 μg/m ³. The daily average concentrations of water-soluble inorganic ions in old coal-fired households ranged from 21.90 to 68.90 μg/m ³, and the mass concentration levels of eight water-soluble inorganic ions were in the order of Cl ^->Na ⁺>NO^-_3 >SO^2-_4 >NH^+_4 >K ⁺+Ca ²⁺+Mg ²⁺. The daily average mass concentrations of water-soluble inorganic ions in new households ranged from 12.53 to 48.04 μg/m ³ and the mass concentration levels of eight water-soluble inorganic ions were in the order of NO^-_3>SO^2-_4 >Cl ^->Na ⁺>NH^+_4 >K ⁺>Ca ²⁺>Mg ²⁺. The indoor PM_2.5 concentration and water-soluble inorganic ion concentration in the old coal-fired households were higher than that of new electrical households in Xuanwei City. Coal burning was the main source of indoor air pollution.