The invention discloses a high-capacity metal lithium powder composite cathode and a preparation method thereof and a multi-layer composite electrode. The high-capacity metal lithium powder composite cathode comprises the following components in part by weight: 1 to 80 parts of metal lithium powder, 10 to 90 parts of cathode powder, 1 to 10 parts of conductive agent, 1 to 4.5 parts of adhesive and 0 to 0.5 part of surfactant. By compounding the metal lithium powder with materials such as graphite, soft carbon, hard carbon, tin and oxides thereof, silicon and oxides thereof and the like, mass ratio capacity and volume ratio capacity of a cathode material are improved, using amount of active substances is reduced, and the battery specific capacity is improved; the specific capacity of the cathode can be adjusted by adjusting the rate of metal lithium to the graphite; short circuit in a battery caused by piercing of a diaphragm through metal dendritic crystal growth can be effectively prevented through the separation of an insulating protective layer, so that the safety performance of the battery is improved; and the metal lithium powder is counteracted with irreversible capacity loss of the cathode, and primary Kulun efficiencies of the graphite, the hard carbon, the soft carbon, the tin, the silicon and other cathode materials are improved.