The energy loss effect in nuclear matter, which is another nuclear effect apart from the nuclear effects on the parton distribution as in the deep inelastic scattering process, can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of the quark energy loss parametrization given in literature and the nuclear parton distribution extracted only with lepton-nucleus deep inelastic scattering experimental data, measured Drell-Yan production cross sections are analysed for 800-GeV protons incident on a variety of nuclear targets from FNAL E866.