The underwater explosion bubbles are mostly non-spherical because of the existence of the different boundaries. In order to find the suitable conditions of applying the spherical bubble hypothesis, the numerical simulation of bubble movement is executed at different boundaries, such as free field in deep water, near free surface, near rigid surface and near elastic boundary. By analyzing the maximum radius and the first pulse periods, it can be put forward that the maximum radius and the bubble first pulse period may decrease near the free surface when the standoff distance is approximate to the maximum radius. The influence of the rigid surface is on the contrary. The influence of elastic boundaries is intervenient. While the standoff distance exceeds the thrice of the maximum radius, the spherical bubble hypothesis is suitable for analyzing the movement of UNDEX Bubbles during the first pulse period at the elastic and rigid boundary conditions, and near the free surface the distance is double the maximum radius.