Abstract: The Lagrange methods in AUTODYN-2D were used to investigate the perforation of the front side of gas-filled pressure vessels. The static stress wall resulting from the inner pressure was simulated by applying a stress boundary along the inner wall. A better correlation between experimental and numerical results was obtained. The numerical simulation was performed to analyze the effects of the projectile diameter,the impact velocity and gas pressure on the perforation of the front wall. The simulation result shows that the effect of gas pressure on the perforation can be neglected. While impact velocity is higher than 3.0 km/s,some micro-crack are initiated at the edge of the circular hole in the vessel wall. Both hole diameter and crack diameter are increased with an increase of the impact velocity and projectile diameters. The critical stress curves with different impact parameters were obtained. While impact velocity is higher than 3.0 km/s,cracks and hole in the vessel walls will lead to a catastrophic failure of vessels.