Abstract: The Euler-Lagrange coupled method in AUTODYN was used to simulate concrete gravity dams subject to underwater contact explosion. The characteristics of damage crack distribution and dynamic responses of the gravity dam subjected to explosion loading from different explosion positions were analyzed. Considering the above characteristics, the aluminum foam was adopted as the antiknock material. Research results show that aluminum foam can effectively reduce the amplitude of shock wave and the dynamic response of the dam; meanwhile, the explosion damage on the dam was decreased and the scope of the cracks distribution was narrowed down. This shows the aluminum foam has good antiknock performance when used in underwater contact explosion.