This paper investigates parametric stabilization of port-controlled Hamiltonian systems with dissipation (PCHD). A controller is designed to make the PCHD system parametric stable as the parameters drift based on its passivity. The form of the controller is related to PCHD system. Thus, the closed-loop system maintains dissipative form and the energy function achieves its minimal value at the equilibrium point determined by the unknown parameter. An excitation system is taken as an example, and the effect of equilibrium point of the system is analyzed as the parameter varies. A controller is designed to make the excitation system parametric stable. Simulation results are given to show the effectiveness of the proposed method.