The invention discloses a water-flow type automatic power-assisted accelerating device used for continuous mouse trapping. The device provided by the invention comprises a water-flow type overbalanced mousetrap and a mouse barrel, wherein the mousetrap is arranged on the ground below an intercept surface; the intercept surface is fixed on the ground, and a bait area is arranged in the intercept surface; baits are dropped in the bait area; the mouse barrel is buried under the ground, and a barrel surface is at most 10cm higher than the ground surface; the mousetrap comprises a base, a mouse through board, a water-flow type power-assisted tube, a weight box and a mouse guard board, wherein the base is detachably arranged on the barrel edge of the mouse barrel; the mouse through board is articulated with the pivot of the base by an axle; the water-flow type power-assisted tube is fixed at the bottom of the mouse through board in an extractable way; the weight box is fixed below the outer end of the mouse through board; and the mouse guard board is detachably fixed above the inner end of the mouse through board. The accelerating device has a simple structure, is efficient and environment-friendly and is easy to maintain.