Abstract: In order to study the contribution of different source regions to ρ(PM_2.5) and pollution characteristics in southern Henan Province from December 2017 to February 2018, the HYSPLIT-4 backward trajectory model was used to simulate the 24-hour air mass in southern Henan Province in winter backward trajectory, combined with online monitoring data of ρ(PM_2.5), and cluster analysis were performed at the same time. The transport characteristics of different trajectories of PM_2.5 with southern Henan Province as the receiving point were studied each month. The potential source contribution function (PSCF) analysis method and concentration-weighted trajectory (CWT) analysis method identified the potential contribution source area and contribution size of PM_2.5. The results showed that: (1) The air quality in Xinyang was the best, followed by Zhumadian and Nanyang. ρ(PM_2.5) in Nanyang, Xinyang and Zhumadian exceeded the National Ambient Air Quality Standards (GB 3095-2012, grade Ⅱ) by 1.5, 1.2 and 1.2 times, respectively. ρ(PM_2.5) showed double-peak characteristics. (2) The backward trajectory cluster analysis showed that southern Henan Province was mainly affected by the long-distance transmission from the northwest and northeast directions and the short-distance transmission from the due south direction. (3) The analysis of potential source areas showed that in addition to the local pollution contributions of southern Henan Province and surrounding cities and counties, the border areas between Hebei Province, Shandong Province and Henan Province, the border areas between Shaanxi Province and Hubei Province, the central and western parts of Shaanxi Province, the northeast and western parts of Hubei Province, the central and northern parts of Henan Province, and the southern part of Shandong Province were the main potential source areas of ρ(PM_2.5). The PM_2.5 pollution process in southern Henan Province was not only related to topographical conditions and local pollution source emissions, but also related to the long-distance transportation from the northeast and northwest and short-distance transmission in the south.