Abstract On the basis of previous researches, compound astragalus polysaccharide (APS) and sulfated epimedium polysaccharide (sEPS) oral liquid (AEO) was prepared. Three hundred and twenty 14-day-old chickens were randomly assigned into eight groups and vaccinated with ND vaccine except for blank control (BC) group, repeated vaccination at 28 days old. At the same time of each vaccination, the chickens in three experimental groups were taken orally with AEO, respectively, at three doses, in two component control groups with APS and sEPS, once a day for three successive days; in injection control group were injected with AEI once, and in vaccination control (VC) and BC groups were not administrated. On days 7, 14, 21, 28 and 35 after the first vaccination, peripheral lymphocyte proliferation, the serum antibody titer, IFN-γ and IL-2 concentrations and on day 35 immune organ index were measured. The results showed that AEO at high and medium doses could significantly promote lymphocyte proliferation and development of immune organ, enhance antibody titer and IFN-γ and IL-2 concentration, which was stronger than actions of AEI and two components. The results confirmed that AEO possessed reliable immunoenhancement and could be exploited into an oral immunopotentiator.