The invention discloses a tunnel smooth blasting powder charging device and method. Based on the smooth blasting peripheral hole non-coupling powder charging mode, a disposable buckle support device is adopted, so that a small-diameter cartridge is symmetrically fixed and supported to achieve the effect that the cartridge is arranged on the axial central line of a blasting shot hole in a filling manner; and the cartridge is precisely supported from the center, the smooth blasting effect is improved to the greatest extent. The tunnel smooth blasting powder charging device comprises a buckle elastic support component arranged at the two ends, in the axial direction, of the cartridge. The buckle elastic support component is provided with a clamping belt. Several fixing clamping teeth are arranged on the clamping belt. A fixed buckle and a movable buckle are arranged at the two ends of the clamping belt correspondingly. The fixed buckle and the movable buckle are each provided with an internal cavity, wherein the internal cavities allow the clamping belt to penetrate through. Springs are fixedly connected outside the fixed buckle and the movable buckle correspondingly.