Polychlorinated biphenyls in environment are analyzed by GC/MS in this paper. The methodto enhance the selectiveness of analysis and the possibility of identification of overlappedpeaks in chromatogram are discussed in detail. Polychlorinated biphenyls in environment are analyzed by GC / MS in this paper. The method to enhance the selectiveness of analysis and the possibility of identification of overlappedpeaks in chromatogram are discussed in detail.