The invention discloses a cylinder gear layering web damping structure and a damping testing method for transmission of the cylinder gear layering web damping structure, and belongs to the technical field of gear damping. An actuator is directly arranged on a layering web, acting force is generated through work of the actuator to push a sliding block to move, the sliding block makes contact with the outer circle of the web, the change of the layer number of the layering web is achieved, accordingly, the transmission error generated in the gear transmission process is changed, and the purpose of reducing gear transmission vibration is achieved. According to the cylinder gear layering web damping structure and the damping testing method, gear transmission vibration can be reduced by actively changing the gear structure.