The uplift and eastward extrusion of the Qinghai- Tibet plateau produced a series of strongly deformed sub- blocks in and around the Qinghai- Tibet plateau, of which the Sichuan- Yunnan block (Chuandian block) is one of the most active tectonic blocks. The Deqin- Zhongdian fault, as one of the west boundary faults of the Chuandian block, displays strong tectonic activity and shows dextral strike- slip movement as well as dip- slip component in late Quaternary. The fault shows obvious normal- slip component from south of the Benzilan- Waka region to the Zhongdian area, but presents thrust movement in the north of the Benzilan- Waka region. The Benzilan- Waka region is the tectonic transit segment of the Deqin- Zhongdian fault, and also the location of turning of the fault strike. All the features indicate that the Benzilan- Waka region manifests itself as the tectonic pivot of the Deqin- Zhongdian fault. The results show that the Deqin- Zhongdian fault caused paleoearthquakes around the Benzilan County at average interval of of 11. 35±2. 4ka with a long- term slip rate of 1. 3~1. 7mm/a. Based on the principle of structural analogy, we suggest that the fault tends to nucleate at the Benzilan- Waka region and the potential magnitude won’t be less than M7 and the potential seismic intensity won’t be less than Ⅹ.