The invention relates to a vane wheel starting mechanism of an alternating-current permanent magnet synchronous motor and a drainage pump. The vane wheel starting mechanism of the alternating-current permanent magnet synchronous motor comprises a shaft sleeve which is connected with a rotor shaft, wherein a starting rib is extruded at the outer side wall of the tubular main body for the shaft sleeve; a vane wheel is provided with a containing chamber which can contain the shaft sleeve; a limit rib is extruded at the inner side wall of the containing chamber; the starting rib and the limit rib are interfered with each other; a shock attenuation elastic body is installed between each group of interferenced surfaces of the starting rib and the limit rib; and the radial direction of the shock attenuation elastic body is adaptive to the radial distance between the inner side wall of the containing chamber and the outer side wall of the shaft sleeve main body. According to the invention, the vane wheel starting mechanism of the alternating-current permanent magnet synchronous motor is improved, the working noise of the permanent magnet synchronous motor can be lowered effectively, although the starting rib and the limit rib are in the plane relationship of mutual interference, the starting rib and the limit rib are not in direct contact, and can not be manufactured to be thinner, smaller and shorter for the dislocation consideration, a larger thrust surface can be ensured, and the vane wheel starting mechanism is abrasion-resisting, is durable in use, and can be suitable for a motor of higher power.