The longitudinally polarized Drell- Yan process is one of the most powerful tools to probe the structure of hadrons.By means of the recent formalism of the polarized proton-deuteron (pd) Drell-Yan, we calculate the ratio of the proton-deuteron Drell-Yan cross section to the proton-proton (pp) one △σpd/2△σpp in the polarized case. The theoretical results can be compared with future experimental data to confirm the nuclear effect due to the 6-quark cluster in deuteron.