Abstract: To access the effect of different infective dose of REV on the specific and nonspecific immune in chickens, immune responses of T lymphocytes to ConA, cytotoxic activity of natural killer cells and cytotoxic T lymphocytes（CTL）and humoral immunity response to NDV vaccine were detected in broilers and specificpathogenfree chickens infected with different dose of REV. The results showed that REV infection, not only at higher dose but at low dose, could cause the immunosuppression of humoral and cellular immune in chickens, which was related to the infective dose of REV. But the cytotoxic activities of NK cell and CTL were enhanced in chickens infected with REV. It could be concluded that REV infection appeared to depress certain immune response but not all the immune responses.