The invention discloses a high-efficiency high-starting-torque disc-type permanent magnet eddy-current shaft coupler, and the shaft coupler comprises a conductor rotor connected with a power source, and a permanent magnet rotor connected with a load, wherein the conductor rotor and the load are set on the same central axis. There is an air gap between the permanent magnet rotor and the conductor rotor. The conductor rotor comprises a conductor back iron disc and a composite structure conductor disc close to the permanent magnet rotor, wherein the conductor back iron disc and the composite structure conductor disc are set on the same central axis. The composite structure conductor disc comprises a radial conductor disc and ferromagnetic wedges which are uniformly distributed on the radial conductor disc. The permanent magnet rotor comprises a permanent magnet back iron disc and a permanent magnet array disposed on the permanent magnet back iron disc. The shaft coupler provided by the invention is high in starting torque, is low in eddy-current loss, is high in transmission efficiency, and is suitable for the application occasions with the higher requirements for the performances, equipment energy saving and heat dissipation.