Abstract: To solve the problem of attitude deflection appeared in projectile oblique penetrating into multi-layered thin concrete slabs, a finite element analysis model and relevant analytical method were proposed for projectile attitude deflection. Firstly, the effect of projectile shape parameters on the rate of angular change was studied for the penetration of the single-layered concrete slab. And then, the attitude deflection trend was analyzed for the penetration of the multi-layered concrete slabs. The research results show that a stable trajectory can be got when a projectile shape with blunt, high length–to-diameter ratio and expanded tail is used to penetrate into multi-layered thin concrete slabs. To arrange a scaling test for the validation of attitude deflection performance, the proportions on thickness of slabs, floor height should be made the same with the length of projectile, making all physical quantities equivalence such as resistance and moment in the movement of scaled projectile.