Abstract: Abstract：The western margin area of Qaidam Basin is close to the juncture between Altun orogen and Qimantag orogen of East Kunlun, where the tectonic movement is very complex. Based on a study of the newest data obtained from 1∶250000 gravity survey, the authors recognized a group of new NNW-SSE trending faulted structures, in addition to NEE-trending Altun fractures and NWW-nearly EW-trending South Kunlun, Central Kunlun and North Kunlun fractures. In this paper, the authors provided gravity evidence for the existence of a group of NNW-SSE trending fractures in this region. Based on an analysis of their characteristics and origins, the authors consider that these fractures are a group of newly rifted strike-slip structures, which have high-angle right-lateral fractures characterized by small fault displacement and long stretches, and they pass through the high-angle right-lateral fractures, belonging to a group of NEE and NWW-nearly EW trending fault zones. Further studies show that these fractures are a group of new faulted zones related genetically to NE-trending movement of the whole Tibetan Plateau. The new findings may have some significance for the understanding of the tectonic movement (especially the new tectonic movement ) and the mineral research in Qaidam western margin area.