Abstract: The raise boring machine uses reverse drilling to break the rock. The rock slag formed by the crushing of the drill bit falls by its own weight, there is no repeated crushing phenomenon, the rock breaking efficiency is high, and the drilling speed is fast. Under the condition of a raise shaft with a small inclination angle, the slag cannot fall stably by its own weight when the drill bit is reamed in a vertical or large angle. The thesis uses the balance formula of the saturated soil in the direction of motion and the improved formula of Scherzler to compare calculations and experiments. The results show that the theoretical calculations are consistent with the experimental results and prove the accuracy of the theory.