Underwater explosion is a severe threat to nearby ocean structures, such as underwater construction, floating vessels. The pressure load produced by underwater explosion of explosives consists of shock wave load and the explosion bubble pulsation pressure load. After the detonation, there will be a shock wave propagating radially outwards and it’s followed by a large oscillating bubble. The shock wave has the first damaging effect on adjacent structures. Then, the collapse and high-speed jet of oscillating bubbles will cause the second damage to structures. When there are double explosive sources near a rigid structure, the mutual superposition of shock waves and the interaction between two bubbles may improve the explosive damage. If the distance between one explosive source and the rigid structure is fixed, the damage force produced by double underwater explosions is related to many factors, like the detonation time difference and the distance between two explosive sources. At first, the pressure field in single explosive source case is numerically simulated by using the AUTODYN in this paper. Next, pressure fields of underwater explosion detonated by double sources at the same time and with time difference are calculated, respectively. The flow fields in double explosive sources case are compared with that in single explosive source case. The effect of the detonation time difference and the distance between explosive sources on the damage force is investigated and analysed in detail.