As the usual method for deriving chemical potential by puce mathematical approach is not closely related to the concept of systems, some issues and fuzzy conceptions have arisen. In the present paper, the chemical potential is derived concisely from single homogeneous chemical constitutent in the open syatem and then the chemical potential for the closed system with single or multiple chemical constitutents as well as the chemical equilibrium equation for open or closed systems are treated of at some length.