In order to study the pressure characteristics of the underwater shock wave in the infinite water and near air-water surface and the physical characteristics of the air-water surface,three-dimensional numerical simulationof infinite water and near air-water surface underwater explosion was carried out based on the arbitrary Lagrangian-Eulerianmethod by finite eldment software ANSYS/LS-DYNA.The interaction between the water and the air during the process of explosion is investigated .According to analysis,we found that in the condition of the depth of detonation remaining unchanged, the influence of air-water surface on shock wave is mainly reflected in reducing the pulse width of incident shock wave and reducing the peak pressure of shock wave with the decrease of sounding depth. The height of water column produced by the same TNT explosive on the air-water surface increases with the decrease of the detonation depth. At the same time, the density distribution near air-water surfaceand the process of water column forming under different detonation depths are qualitatively analyzed, which is also reproduced with three-dimensional numerical simulation method.With the numerical simulation method, the characteristics of the shock wave values are analyzed and certify that the model has better calculation accuracy compared with the empirical formula,and the process of underwater explosion near air-water surface is also represented.