电动力学通过让磁场下磁偶极子受到的作用力等于势函数的负梯度，定义稳恒磁场下磁偶极子的势函数.从这个定义并不能知道该势函数的物理意义.本文从场的角度分析势函数的意义，指出磁场下宏观磁偶极子的势函数和原子磁偶极矩的相应能量虽然具有相同的表达式，但是物理意义却不同，后者实际上是原子内能的一部分.

A static external magnetic field exerts a force on magnetic moment which is equal to negative gradient of the potential, that is the definition of the potential in electrodynamics. However, the physical meaning of the potential is not given by this definition. We will discuss the physical content of the potential, showing that the potential of a macroscopic magnetic moment and magnetic field-depending energy of an atom are different in physics, although they have the same expression. The one for the atom is part of the internal energy of the atom.