Abstract：According to the gravity and magnetic map, a fault named Wudu-Wenxian extends along the Wudu-Wenxian-Lixian line, with obviously different gravity and magnetic features on both sides. It has greater size and tectogenetic intensity than Longmeshan fault, and is probably the boundary between Yangtze platform and Songpan-Ganzi oregen. Dextral strike slipping generated the southwestward movement of the southeast block and the northeastward movement of the northwest block, with characteristics of regional strike slip and compression. Therefore, the Wudu-Wenxian fault not only serves as a regionalized strike-slip fault but also has the same fault significance as the Altun fault. The eastern margin of Tibetan plateau must have experienced a 100 km northward movement along this fault, as inferred by the magnetic anomaly offset of East Kunlun region.