Abstract: According to the in-situ information about the load-carrying capacity descent of pier rock mass foundation, the multiply anchor-pile technique in a single bore was adopted in the reinforcement. The mechanism of the technique was analyzed in the rudimental stage. By using of numerical simulation, the load-carrying capacity of pier foundation and anchor-piles were also calculated after reinforcement. The result shows that, after reinforcement the load-carrying capacity of pier rock mass foundation was increased largely. Under the loading of 600 kN/m from the pier, the maximum value of vertical displacement of anchor-piles and rock mass was less than 2 mm, and that it is keeping synchronous in the displacing process.