Abstract: After sampling PM_2.5, the filter membrane was extracted 3 times ultrasonically with the mixture of n-hexane and dichloromethane (volume ratio of 1∶1). The combined extract was concentrated, and then diluted to 5.0 mL with water. GC-MS/MS was applied to the determination of 7 indicative polychlorinated biphenyls and 16 polycyclic aromatic hydrocarbonds in the sample solution. The DB-5MS UI chromatographic column was used for GC separation and the multiple reaction monitoring mode was adopted in MS/MS determination. Linear relationships between values of peak area and mass concentration of 7 indicative polychlorinated biphenyls and 16 polycyclic aromatic hydrocarbonds were kept in the same range of 5-200 μg·L^-1, with detection limits (3S/N) in the range of 0.002-0.019 ng·m^-3. On the base of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 80.4%-108%, with RSDs (n=6) of determined values in the range of 0.90%-5.0%.