Abstract: It has operated safely for 30 years since it put into operation for Liujiaxia hydropower station. During the time, the discharge structures have long suffered from abrasion by high speed flow with sand, and made it severely destroyed. Thus reinforcement have been carried out including coating tunnel body with epoxy mortar, sticking new steel plate on the surface of original steel lining, make it possible to construct in the dry and optimizing the gate opening manner. Those steps have achieved good effect.