The invention belongs to the technical field of semi-solid metal forming and provides a method and a device for manufacturing semi-solid metal by using a serpentine vibration channel. Molten metal with certain superheat degree is poured into an upper opening of the vertical or oblique serpentine channel with a mechanical vibration characteristic, the superheated molten metal downward flows to a lower outlet of the serpentine channel along the inner wall of the serpentine channel under the mechanical vibration effect to form the semi-solid metal. The device comprises a pouring ladle, the superheated molten metal, a pouring cup, the serpentine channel, an electric-excitation mechanical vibrator, an electric-excitation vibrator controller, the semi-solid metal, a collecting container, a pressure chamber, a punch pin and the shaping and ejector die portion. The method and the device have the advantages that cooling, nucleation and crystalline grain dissociation of the molten metal in the serpentine channel are promoted by utilizing the electric-excitation mechanical vibrator, the hanging amount on the inner wall of the serpentine channel is reduced, the cleaning work difficulty is reduced, the metal re-melting amount and the melting energy consumption are reduced, and the device is simple in structure and low in production cost and is suitable for manufacture of the semi-solid metal.