Abstract: The source apportionment of PM_2.5 is extremely important for effective control of emission sources, which has become an urgent need for air pollution control at present. In order to clarify the PM_2.5 pollution characteristics and sources in Zhumadian, the ambient PM_2.5 samples were collected at two sampling sites in Zhumadian from January to March 2019, and the chemical characteristics of PM_2.5 species were analyzed. A temporal and spatial source apportionment method was developed and applied by combining the Positive Matrix Factorization (PMF) and the backward trajectory model. The results indicated that the annual mean concentration of ambient PM_2.5 was 117 μg/m³, of which NO₃^- and organic carbon (OC) were the main species. During the sampling period, the average concentrations of OC and EC were 18.2 and 5.2 μg/m³, respectively, and the mean ρ(OC)/ρ(EC) ratio was 3.5, indicating the significant effect of vehicle exhaust and coal combustion. The ρ(SO₄^2-) and ρ(NO₃^-) showed a significant correlation (R=0.80, P < 0.01), implying a high degree of homology. In the haze episodes, the average concentration of SNA (Sulfate, Nitrate and Ammonium) was 61.5 μg/m³, which was significantly higher than the clean-air period. During the haze episodes, SOR and NOR values were 0.42 and 0.39, respectively, suggesting an obvious formation process of secondary particles. The concentration and proportion of crustal elements such as Si, Al, Mg during the haze episodes were higher than in the clean-air period, likely indicating an important influence of dust sources. The results of source apportionment indicated secondary sources were the primary contributor (32.6%) during the heating period, followed by the mixed source of dust and biomass burning (26.4%), vehicles exhaust (21.4%), coal combustion (13.2%), and industrial sources (6.3%). The primary sources during the two haze episodes were vehicle sources (46.2%) and secondary sources (54.5%). Secondary sources (45.2%) and coal combustion (29.8%) were the major contribution sources during the clean-air period. The contribution of the mixed source of dust and biomass burning at Tianfang site (29.3%) was significantly higher than that of Caiyinchang site (23.3%), while that of coal combustion at Caiyinchang site (16.5%) was significantly higher than at Tianfang site (10.1%). There was no significant difference in the contributions of other sources. The east, southeast and northwest were the major contribution directions of sources of the two sampling sites. This research showed that secondary source was the largest contribution source during the heating season, haze episodes and the clean-air period. Compared with the clean-air period, the contribution of the mixed source of dust and biomass burning increased apparently during the haze episodes. There was a spatial difference between source contributions, and the main contribution directions of emission sources were in the east, southeast and northwest.