Based on an extended effective electron-phonon model, considering the strong correlation interaction between electrons, the Bogoluibov approximation of electron operators is presented and an effective phonon-electron interaction is derived. It is shown that through exchange of virtual electrons, longitudinal phonons with oppo-site wave vectors can feel an effective attractive force and form phonon pairs with an electron. For an approprate phonon density, a new superconducting phonon state with the high critical temperature appears.