Anti-slide piles are widely used in slope reinforcement projects and the effect is remarkable. However, in the management of large-scale landslides, multiple-pile joint action is often needed to strengthen the anti-slide effect, and the analysis of anti-slide effect lacks theoretical basis. In this paper, a joint coupling model of h-shaped pile, beam between piles and anchor cable behind piles is established by using structural elements. A numerical model-based automatic application method of h-shaped pile is developed by identifying the potential sliding surface using self-development program, through which the pile section parameters can be automatically calculated, and then the finite difference method is used to analyze the deformation stability. On this basis, the influence of h-type anti-slide pile combined support and single pile support on slope stability under rainfall condition is compared and analyzed. The results show that the combined support of h-type anti-slide pile is effective in large landslide support engineering, and the pile body can withstand greater anti-slide resistance and deformation. The position of pile affects the supporting effect, which is best when the anti-slide pile is arranged in the middle position of the landslide. With the support position from the bottom to the top of the slope, the safety factor of the slope increases first and then decreases. The research results can provide reference for the practical application of landslide support engineering.