We calculate the Coulomb failure stress changes caused by the 21 March 2008 Ms7.3 Yutian, Xinjiang earthquake on its neighboring faults. The result shows that the Coulomb failure stresses increased along the southwest and northeast segments of the Gonggacuo fault, the east and west segment of the Kengxiwar faults, the west segment of the Pulu fault, the west segment of the Lungmu Co—Bangdag Co, the Altyn Tagh fault and the western Kunlun thrust fault by 6.9×104 Pa, 4.4×103 Pa, 8.0×105 Pa, 2.8×103 Pa, 2.3×104 Pa, 5.7×103 Pa, 1.6×103 Pa and 1.1×103 Pa, respectively, decreased along the central segment of the Gonggacuo and Kengxiwar faults, the east segment of the Lungmu Co—Bangdag Co fault, the central segment of 〖JP2〗the Pulu fault, and the north segment of the Karakorum fault by 3.9×105 Pa, 5.8×105 Pa, 1.5×104 Pa,1.5×104 Pa and 1.1×103 Pa, respectively. We estimated that the characteristic earthquake delayed 1~127 years in the central segment and advanced 2~138 years by the Yutian earthquake according to the slip rate on this fault. The Coulomb failure stress change caused by the 8 October 2005 Pakistan earthquake and projected on the fault plane and slip direction of the Yutian earthquake is 10~20 Pa, and is in favor of its occurrence. The Yutian earthquake has a normal faulting mechanism. Its origin is interpreted as the result of NNE intrusion of the