A trapezoidal cross-section vertical pre-stressed anchor anti-slide pile is a new type of structure to manage water damage related landslide,and the characteristics of soil arch between piles are different from those of conventional anti-slide piles.It is obviously unreasonable to continue using the traditional anti-slide pile and soil arch model.In this paper,the formation characteristics of soil arch between piles are analyzed,the calculation model of trapezoidal anti-slide pile is established,the calculation formulas of pile spacing in different forms are derived respectively,and the pile spacing of each algorithm is compared by engineering application.At the same time,based on the calculation of pile spacing,the influence of pile side angle on pile spacing is analyzed,the design value range of pile side angle is defined,and the better angle value is discussed,providing theoretical reference for projects of the same kind.