Abstract: This paper presents the electric enthalpy density-based Hamilton principle and its application in solving the problems with coupled mechanical and electrical properties of piezoelectric materials. The analytical solutions are derived for the deformations and electric potential of two simple structures. The resulting solutions are compared with the existing results, and the errors in these results are pointed out. The results demonstrate that the electric enthalpy-based Hamilton principle is a simple and powerful model to solve electric-mechanical coupling problems of piezoelectric materials. The model presented here can be also used for the mathematical model of finite element analysis of piezoelectric materials and structures.