Abstract: Based on the proportion of individual chemical to the total amount of persistent organic pollutants (POPs) (relative compositions) and cluster analysis, the probe technique of POPs'' relative composition was conducted to investigate the sources and long-range atmospheric transport of POPs across the Tibetan Plateau. In this study, the published data of 16passive sampling sites were employed, and sampling sites (across the Tibetan Plateau) with similar chemical sources were clustered into different groups. Focusing on each group, the probable POPs source as well as regional or long distance transport contributions can be inferred. The results indicated that the local emission was the major source of atmospheric hexachlorobenzene (HCB) on the Tibetan Plateau, and its high relative compositions (25%-74%) appeared in sites close to cities/towns where anthropogenic activities were intensive (e.g., Bomi, Golmud, Yushu, Lhasa, Lhaze, Gongbog''Yamda, Lhaze and Nagqu). The sites near southern fringe of the Tibetan Plateau (i.e., Everest, Ranwu and Saga) had high relative compositions (more than 40%) of hexachlorocyclohexanes (HCHs) and α-Endosulfan (current-used pesticides in India), implying the long-range atmospheric transport from South Asia. When excluding HCB in cluster analysis, the sampling sites in mountain valleys (Lunang, Lhaze, Lhasa, Xigaze, Gongbog''Yamda, Qamdo), Nagqu, and Gar were classified into the same cluster due to their higher compositions of o, p''-DDT (mean value 40%). The local agricultural usage of dicofol was the most likely source for o, p''-DDT.