Abstract: The relations between unstable blocks and key blocks in the complex sloping rock mass should be accurately considered.Therefore,we could effectively design the reinforcement and the engineering project.The sloping rock mass of water-diversion tunnel in Shuanggou Power Station had been cut into unstable landslide systems by faults and fissures,and suddenly fallen during excavation.Considering that the sloping rock mass would collapse furthermore,the design of pre-stressed anchor of reinforce system was conducted by the sliding mechanism with double slip surfaces and slope stability analysis.In fact,the stability of sloping rock mass was effectively kept and the river closure in construction stage was ensured.