The penetration behavior is very important for the semi-armor-piercing warhead. The oblique penetration behavior of the projectile with cutting mechanism was studied numerically by using the finite element code LS-DYNA. The penetration performance of the projectiles with and without cutting mechanism were compared respectively on the limit ricochet angle, the residual velocity after perforation, the dimension of the hole and the sliding distance of the projectile on the target before perforation. It shows that the numerical results agree well with the experimental ones. It reveals that the anti-ricochet effect of the cutting mechanism on the projectile is not so obvious but the dimension of the hole created by the projectile with cutting mechanism is much larger than that of the traditional projectile. The deflection and attack angle of the projectile with cutting mechanism change to different extent compared to the case of the traditional projectile. An optimized projectile with half cutting mechanism was proposed, and the simulated results showed that the anti-ricochet ability of this optimized projectile is better.