Abstract: Application of MS/MS to Forensic ScienceXu Jianzhong(Institute of Forensic Science,Ministry of Public Security, Beijing 100038,Ching)Abstract:In this paper it describes the identification of residues of explosives, narcotics and thier metabolites using MS/MS technique. A direct probe made used for the analysis of above mentioned mixture samples has the advantages that it saves time consuming in sample treatment and also obtains the reliable data available to diagnosis. The MS/MS technique will have extensive prospect in the appliction of forensic science.Keywords: MS/MS, explosive, narcotic