指出现有方法计算磁力存在的问题. 推导了作用于媒质的磁场力和磁力矩计算公式，可用于分析媒质在磁场作用下的形变和运动趋势，并给出应用实例. 本文进一步完善麦克斯韦应力公式，在一定程度上弥补虚位移法的不足，同时为法拉第观点和等效磁荷法提供理论印证.

Problems of calculating magnetic force by existing method are pointed out. The calculation formulas of magnetic force and magnetic moment acting on the medium are derived，which can be used to analyze the deformation and movement trend of the medium under the action of magnetic field，and examples are given. In this paper，the Maxwell stress formula is further improved. To some extent，the formulas in this paper make up for the deficiency of virtual displacement method，and provide theoretical verification for Faraday’s point of view and equivalent magnetic charge method.