In this paper we present an improved nuclear density model. We have found the nuclear effect parameters’ formula RAV(x,Q2) and RAS(x,Q2) for the valence quark distribution and sea quark distribution in the nucleus, in which we have used the relation between the nuclear density and the mean binding energy in nucleus. By using the model, we can well explain the experimental data of the of Drell-Yan process in P-A.