In this paper

based on the electromagnatic field theory

the magnetic action of the rare earth magnet gear transmission is divided into three parts

i.e. the actions between the two equivalent currents

between the equivalent current and magnetized field of the medium

between the two magnetized fields of the media. With help of the formulas of magnet field characteristics which are derived using the integral equation method

the torque formula of the magnet gear transmission is derived

and the torque features are analyzed.