Some properties of the strong- and weak-coupling polaron in an asymmetry quantum dot are studied by the linear combination operator and unitary transformation methods. The ground state energy and the ground state binding energy of the polaron as a function of the transverse and longitudinal effective confinement length of the quantum dot and the electron-phonon coupling strength are obtained. It is shown that the ground state energy and the ground state binding energy of the strong- and weak-coupling polaron will increase strongly with the decreasing of the transverse and longitudinal effective confinement length of the quantum dot.