In order to improve the damage effect of the projectile under the condition of weak-restriction scattering, the hole-enlarging capability for thin shell projectile penetrating steel plate with different attack angles was researched by the methods of the numerical simulation and the experiment. The finite element model of the projectile penetrating steel plate was established. The attack angles included the impact angle formed with the plate normal and the velocity direction and the cross angle formed with the projectile axis and the velocity direction. The penetration process of the different attack angles was simulated. Based on the analysis for the impact acceleration of the projectile parts and the invariability of the explosive, the size of the enlarging holes with different attack angles was calculated and compared with the experiment results. A good agreement of the simulation and the experiment was obtained, and the relative error was less 10%. The result shows that this method is suitable for studying the hole-enlarging capability for projectile penetrating steel plate with weak-restriction scattering.