Chlorinated aromatics and alkanes have important use value because of their flame retardancy，but they need to be monitored when used in recycled pulp. This paper report the use of palladium acetate/ Activated carbon activated by nitric acid as an online catalyst in the determination of chlorinated aromatics and chlorinated alkanes in recycled paper products with Gas Chromatography-Tandem Mass Spectrometry method, by which significantly improve the sensitivity of the method and dramatically lower the detection limits.