A hydraulic accumulator-based controllable pressure injection apparatus includes a pressure storage system, a pressure maintaining system, a sealing system, and an injection system. The pressure storage system includes a front half part of a pressure cylinder, an annular piston and a middle connecting body; the pressure maintaining system includes an energy accumulator, a rear half part of the pressure cylinder, and a rear end cover; the sealing system includes a hydraulic propulsion cylinder, a propulsion piston, a front end cover, a sealing tube, a thickened end part, and an expansion rubberhose; and the injection system includes a hydraulic valve body, and an injection gun tube. The hydraulic accumulator-based controllable pressure injection apparatus can quickly apply pressure to thehole bottom of a hole drilling in a hydraulic manner, so that rock is damaged by pulling, and the drivage efficiency of hard rock is improved.