In this paper, a novel magnetic gear motor (MGM) with nonuniform air gap Halbach array magnetization is proposed to study the influence of temperature change on its electromagnetic performance. The inner PM adopts the Halbach array magnetization structure, which makes the inner rotor air gap have an uneven air gap structure, thereby improving the air gap flux density. In addition, the air gap magnetic field of MGM is analyzed by the finite element method (FEM), and the 3D model of the motor is established. The main losses of the motor, including copper loss, eddy current loss, and hysteresis loss are coupled to each component as a thermal source and studied by magnetothermal coupling. The transient variation characteristics of loss distribution during MGM operation are comprehensively considered. The temperature variation of each component of the MGM with time during load operation is studied in detail. The results show that the temperature of the PM of the MGM is close to 91.8 • C when the rated load is running, and the PM of the motor does not undergo irreversible demagnetization.