The conserved quantity of the perturbed Kepler system was studied by using the direct integral method and Noether method. One conserved quantity , different from the Hamiltonian, was obtained by two different methods .The dimension of the conserved quantity is identical with the RungeLenz vector＇s , so we can name this conserved quantity “analogous RungeLenz vector conserved quantity” . Furthermore, the Noether symmetry, the Lie symmetry and the Mei symmetry of the conserved quantity were also discussed. The research indicates that the infinitesimal transformations of the conserved quantity are all Noether symmetry, Lie symmetry and Mei symmetry.