Abstract:The deformation and failure models of rock are presented according to the characteristics of local deformation and failure of rock. The formula of stress on the projectile is obtained from relation of momentum conservation on the wavefront and continuum condition of the surface of projectile. The results are different from the existing formulae both in China and abroad. The scale relation of penetration and perforation is clarified by the relation of energy transfer in the process of fragmentation zone to radial crack zone. A generalized formula for the penetration depth and the perforation process on a sound physical background are obtained from the non-deformable projectile with conical nose. By comparison with current empirical equations, the proposed formula is validated.