Abstract: The studies on soil arching effect of anti-slide piles are mainly based on the continuous medium theory at present. It is difficult to consider the distribution of soil particle size and other important factors. It is necessary to further reveal the arching mechanism of soil which is non-continuous and non-uniform material. Particle flow code (PFC) is used to study the effects of anti-slide pile size, spacing, pile-soil relative deformation rate and soil particle size distribution on the formation, development, destruction and re-formation process of the soil arch. The effects of the above factors on the maximum bearing capacity, residual bearing capacity of the soil arch and the pile-soil load share ratio are revealed. The results show that the effects of these factors are significant. The maximum bearing capacity of the soil arch decreases with the increase of the ratio of the pile spacing to the width and increases with the increase of pile-soil relative deformation velocity and soil particle distribution width. The residual bearing capacity and the pile load distribution ratio decrease with the increase of the relative ratio of the pile spacing to the width and soil particle distribution width, and increase with the increase of pile-soil relative deformation velocity. Therefore, the design and location of anti-slide piles should consider relevant factors as many as possible to optimize the design and save investment.