The utility model relates to a structure is loaded in nuclear island bottom plate protective layer blasting big gun hole, including the hole body, the drill way department of the hole body is equipped with the section of clogging, the internal blasting cap that is equipped with in hole, and its characterized in that is equipped with cushion in the bottom of the hole body, is equipped with the enhancement powder charge section that line charge density is big on cushion, is equipped with the normal charge section that line charge density is little on strengthening the powder charge section, leaves the air column between the normal charge section and the section of clogging. The utility model discloses can lengthen explosion pressure uses pore wall and hole bottom time to mitigate the detonation -wave peak pressure and to the impact of base member medium, make the blasting energy obtain reasonable distribution and utilization, reduce the bold rate, reduce seismic effects, reduce the foundation, promote the economic benefits of blasting, can play the guard action to secret nuclear island bottom plate integrality stability simultaneously, gain the benefit of good economy.