A drill pipe lifting liquid injection device for a core drill comprises a main shaft connected with a drill pipe. The upper portion of the main shaft is sleeved with a mandrel. A sealing device is arranged between the outer wall of the lower portion of the mandrel and the inner wall of the main shaft. A limiting boss for limiting the sealing device is arranged on the inner wall, below the sealing device, of the main shaft. An adjusting pressing sleeve used for adjusting the sealing device and guaranteeing the water sealing effect is arranged on the sealing device. An installing window is arranged on the main shaft which is further provided with a drill pipe lifting buckle detaching mechanism. The drill pipe lifting liquid injection device is compact and simple in structure and convenient to disassemble and assemble, is installed at the upper end of the initiative drill pipe of the drill, can replace a faucet to achieve the situation that when the drill normally runs, flushing liquid flowing out of an earth surface slush pump is conveyed into a hole bottom drill pipe column through the device, the initiative drill pipe rotates, and a slip casting pipe does not rotate, and can also replace an elevator to normally take down a hole bottom drilling rig.