Aiming at the problems of long transmission chain, low system efficiency and high noise of traditional asynchronous motor driven jacquard air jet loom, a permanent magnet motor direct-drive system is proposed. In order to ensure the cloth quality, the genetic algorithm is used to optimize rotor eccentricity and pole arc coefficient and reduce torque ripple. Due to the continuous change of the load of jacquard air jet loom, the magneto-thermal performance of the motor is constantly affected. A calculation method of transient magneto-thermal bi-directional coupling is proposed to approach the steady-state temperature rise step by step. The temperature rise distribution law and electromagnetic performance of the motor at different power points are compared and analyzed, and the optimal power point is obtained. Finally, a 3.1 kW prototype is developed and tested, and the experimental data are basically consistent with the simulation results. The rationality of using transient magneto-thermal bi-directional coupling to approach steady-state temperature rise successively and select the optimal power point is verified, which provides a basis for the design of direct-drive permanent magnet motor in jacquard air jet loom.