Abstract: The Hamiltonian containing shielding effect parameters is established by considering the helium-like atom electron nuclear shielding effect,the ground state energy of the helium- like atom is investigated by the perturbation theory. In comparison with non- parametric perturbation method,the energy acquired by parameter perturbation method,exactly the same as by the variational method,is close to the experimental values. It indicates that the parameter perturbation method provides us a new approach to study the multi- electron atomic levels and the fine structure of atomic levels.

Key words: helium-like atom, the ground state energy, parameter perturbation method