Abstract: 3-week-old SPF chickens were immunized with triplex oil emulsion vaccine ND-IB-EDS with different doses of 0.1, 0.2, 0.3 and 0.5 mL prepared by institute of Animal Husbandry and Veterinary Medicine of Beijing Academy of Agriculture and Forestry. ND and EDS HI antibodies in chickens were detected after immunization for 3 weeks and the chickens were challenged with virulent NDV Beijing strains; In addition, SPF chickens were immunized with H 120 live vaccine at first immunization and that were immunized with triplex oil emulsion vaccine at 0.1 - 0.5 mL per chicken resp. at second immunization, and then the IB HI antibodies in chickens were measured after two immunities. The results showed that immune dose of 0.1 mL could produce better immune effect and therefore the minimum immune dose of the ND-IB-EDS vaccine was 0.1 mL per chicken.