  In order to overcome the shortcoming of nonconservation of nuclear momentum
existing in the original $Q^2$-rescaling model(O$Q^2$RM) and avoid introducing
nuclear shadowing factor, we proposed a double $Q^2$-rescaling model(D$Q^2$RM)
for the parton distributions of the bound nucleon. Using the experimental data
of lepton-nucleus deep inelastic scattering(DIS) and the condition of the
nuclear momentum conservation, the $Q^2$-rescaling parameters of various
partons for Sn, Fe, Ca and C nuclei are determined. The rescaling parameters of
valence quark distributions are larger than unity and graduauly increases with
atomic number A, on the contrary, the rescaling parameters of sea quark
distributions and gluon distributions are smaller than unity, and slowly
decreases with A. By using this model, the experimental data of the DIS
process, the nuclear Drell-Yan process and $J/\psi$ photoproduction process are
consistently and quite satisfactorily explained. Key words --- parton
distribution functions, Nuclear effect, Double $Q^2$-rescaling model.
