Auto-control adjustable speed asynchronous magnetic coupling was designed according to principles of electromagnetic induction. Its development can effectively solved the vibration leading to the damage of mechanical coupling and the surrounding parts caused by rigid mechanical coupling link, as well as realized motor soft starting by controlling output speed in different torques. Based on the above working requirement, a novel magnetic coupling structure suit for auto-control by PLC in this paper was created. The motive simulation analysis of body structure and the simulation of magnetic torque at different air-gap length were obtained separately by ADAMS and ANSOFT. The results showed that the structure of auto-control adjustable speed asynchronous disk magnetic coupling was reasonable in practical condition.