Abstract: Large landslides are typically characterized by the multi-sliding zones structure, influenced by engineering geological conditions. However, the impact of the soil arch effect on multi-sliding zones landslide is often overlooked in studies of anti-slide piles reinforcement. Therefore, numerical simulations of multi-sliding zones landslide-anti-sliding piles system under thrust loading were conducted. These simulations investigated the effects of pile spacing and embedment depth on the soil arching effect across different motion modes and evaluated the reinforcement effectiveness under various design parameters. The results show that: (1) During landslide movement in multi-sliding zones, the stress around the pile exhibits a bidirectional, multi-level soil arch distribution along the depth, manifesting as the phenomenon of “soil arch behind pile - soil arch in front of the pile-soil arch behind pile”. (2) As the pile spacing decreases from six times to two times the pile diameter, the end-bearing soil arch effect at various depths becomes more pronounced, thereby improving the reinforcement effect. Conversely, when the pile spacing increases from two times to six times, the frictional soil arch between the piles gradually becomes the dominant anti-slide mechanism, diminishing the reinforcement effectiveness. (3) Changes in embedding depth do not alter the type of soil arch at different depths but affect the strength of the soil arch. (4) When shallow sliding dominates, reducing pile spacing enhances the reinforcement effect of anti-slide piles; when deep sliding dominates, increasing the embedment depth improves the reinforcement effect.