In order to study the concentration and source of PAHs in PM2.5 during heating and non-heating periods in Changchun City, 80 samples were collected from October 25, 2017 to November 30 and March 19, 2018 to April 30, 2017, the mass concentration of PM2.5 was analyzed, and 16 PAHs were analyzed by GC-MS, the source was analyzed by ratio method, and the health risk assessment model of USEPA was used Health risk assessment. The results show that the average mass concentration of PM2.5 during the heating period is 283.37 μg·m-3, which is 3.78 times of the secondary daily standard limit of GB3095-2012. Among them, the concentration of PYR in 16 PAHs is the highest, mainly in the middle and high ring, accounting for 76.03%; the average mass concentration of PM2.5 in non-heating period is 195.81 μg·m-3, which is 2.61 times of the secondary daily standard limit of GB3095-2012. Among them, the concentration of PYR in 16 PAHs was the highest, mainly in middle and high ring, accounting for 77.41%. The characteristic ratio method shows that the pollution in heating period mainly comes from the mixture of coal combustion and automobile exhaust emission, while in non-heating period it mainly comes from the combustion of gasoline and diesel. During the sampling period, the carcinogenic risk values of children and adult men were ILCRdem >ILCRing >ILCRinh, while that of adult women were ILCRing >ILCRdem >ILCRinh, and the carcinogenic risk values of heating period were higher than that of non-heating period. The ILCR value was lower than 10-6 in all groups, and the level of carcinogenic risk was acceptable. It provides scientific basis for the comprehensive prevention and control of air pollution and environmental management in Changchun.