Based on numerical simulation and experimental verification, a research has been conducted on the variable regularity of rammed soil-cement tapered piles peak stress under vertical loading. Experimental results show that the depth corresponding to the pile peak stress is basically a fixed value, which has little to do with the vertical loading, for wedge piles with identical wedge angles. A concept of pile peak stress depth ratio has thus been proposed: the relationship between the depth radio of pile peak stress and wedge angles can be approximately fitting with that between straight lines and parabolic sections with a high degree of fitting.