Abstract: In order to determine the therapeutic effect of egg yolk antibody against the novel duck reovirus（NDRV） at different times, 4-day-old healthy susceptible ducklings were challenged with new duck reovirus virulent RPVA1301-Z strain, and 0.5 ml of new duck reovirus yolk antibody was injected the subcutaneously after 24 h, 48 h, 60 h and 72 h infection. The results showed that the cure rate of egg yolk antibody against ducklings infected after 24 h was 95%; the cure rate of ducklings infected after 48 h was80%; the cure rate of ducklings infected after 60 h was 50%; the cure rate of ducklings infected after 72 h was 35%. Injection of the corresponding yolk antibody within 24～48 h had a better therapeutic effect on ducklings after infection with the new duck reovirus.