Abstract: In excavation engineering, an inclined-vertical retaining pile system can be formed by connecting the cantilever piles and the inclined piles. The previous case histories indicate that the inclined-vertical retaining piles have the advantage in overturning resistance and deformation control. However, the insight into the working mechanism of inclined-vertical retaining piles is limited. Three mechanisms are proposed in this investigation, that is, frame effect, supporting effect, and gravity effect. Taking the deformation of retaining structures and the ground settlement as the criteria, the contribution of these work mechanisms is analyzed. The results indicate that (1) The formed frame system can significantly decrease the structural deformation and ground settlement. (2) the side friction in inclined piles is vital to the supporting effect on the cantilever piles. (3) the soil between the inclined and vertical piles has a limited effect on the structural deformation.