The vibration frequency and effective mass of the strong-coupling polaron in an infinite quantum well were derived by using improved linear-combination-operator and variational method. The effects of well width and electron-LO phonon coupling strength on the effective mass of polaron were discussed, The influence of velocity of polaron on the vibration frequency,ground state energy, ground state binding energy and effective mass were depicted. Numerical calculation illustrates that the effective mass will decrease with increasing well width,and it will increase with increasing the coupling strength;the vibration frequency,ground state binding energy and effective mass of strong-coupling polaron will increase with increasing the velocity of polaron; and the ground state energy decrease with increasing the velocity of polaron.