Kusongmuxieke mountain front fault is one of important border faults of the north fringe of rejuvenated orogenic belt in west segment of north Tianshan, it is found and determined in our research that it is an active fault. The fault can be divided into three segments. The east segment mainly consists of four en echelon faults with length of 9～13 km, and still moves inten- sively in Later Pleistocene and Holocene Epoch. Since Later Pleistocene, vertical slippage of single fault has been 3～4 m, vertical active rate is 0.23～0.33 mm/a, and vertical slippage of single fault is 0.5～0.8 m since Holocene Epoch. New movement of the middle segment dislocates different geomorphologic units which formed from Middle Pleistocene to Holocene Epoch, forms multilevel fault escarpments and a 8～10 km long earthquake deformation belt. Since Later Pleistocene the vertical active rate is 0.5 mm/a. The west segment has no movement since Later Pleistocene.