Abstract: In the article, eddy current loss power of permanent magnetic coupling is analyzed, according to the principle of electromagnetic induction and the law of conservation of energy, the relationship between eddy current loss and its influence factors is obtained; the stable running state and overload state temperature rise of the permanent magnet coupler is analyzed by finite element simulation. The results show that under the same load conditions, the increase of air gap thickness and the conductor resistivity, the decrease of copper thickness will cause the increase of eddy current loss; for the 40 kW mine-used permanent magnetic coupling, natural air cooling mode can meet the cooling requirements of torque load less than 300 N·m, under the condition of overload, permanent magnetic coupling will rise to Curie temperature in 45 sand and cause permanent damage, motor should be closed in time.