Abstract: The perforative crack found at gravity buttress at right bank of Dashankou arch dam. The author considered the cracks at the gravity buttress on two banks caused by temperature stress by analyzing the cause of cracks. Although the crack did not resulted in stress increase of dam body and unstable in dam shoulder, the stress at battress heel exceeded the quantity defined by specification. This paper puts forward crack seal and the treatment scheme of pre-stress anchor in vertical direction.?