Three hundred and fifty 14-day-old chickens were randomly assigned to 7 groups. At the same time of vaccination with Newcastle disease vaccine, the chickens in experimental groups were injected with propolis flavonoids liposome (PFL) at three doses, PF and blank liposome, respectively. The titer of serum antibody, concentrations of immunoglobulins G (IgG) and immunoglobulins M (IgM), activity of lymphocytes proliferation and concentrations of cytokines were measured. The results showed that three doses of PFL could significantly enhance antibody titer, concentrations of IgG, IgM, and promote lymphocyte proliferation, interferon-γ and interleukin-2 secretion, and its high and medium doses possessed the best efficacy. In general evaluation, the efficacy of PFL was the best, with certain of dose- and time-effect relationships. These findings indicated that the immunological activity of PF could be enhanced with liposome encapsulation.