Underground double-acting accelerator

The invention provides an underground double-acting accelerator. The underground double-acting accelerator comprises an upper joint, an upper shell, a middle shell and a lower shell, which are in threaded connection with one another in turn from top to bottom and the interiors of which are communicated with one another, wherein an axial pressure-stabilizing structure is arranged in the upper shell; the lower end of the axial pressure-stabilizing structure extends into the middle shell; a peripheral impact structure is arranged in the middle shell; the upper end of the peripheral impact structure is resisted against the lower end of the axial pressure-stabilizing structure; the lower end of the peripheral impact structure is penetrated through the lower shell and extends out of the lower shell. According to the invention, the axial pressure-stabilizing structure is arranged for stabilizing the axial pressure endured by a drill bit and applying an axial stable push force to the drill bit, and meanwhile, the peripheral impact structure is arranged for supplying the peripheral impact force to the drill bit and increasing the drilling speed.