Abstract: To investigate the effects of changing the explosive point on the missile air contact explosion damage（on stiffened plates），finite element simulations are conducted to analyze the damage processes， crevasse sizes and distortional energies of stiffened plates in eight different cases（a combination of two explosive charges and four explosive points）. The results show that when the same amount of explosive explodes at different points，the discrepancy of crevasse sizes can go beyond 20%. Also，the crevasse shapes are markedly distinct even with less explosive charge. Particularly，when the explosion occurs at the decussation of stiffeners，the distortional energy can be twice as much as that at the centre，and the distortional energy of the whole plate can be 40% or more.