In order to identify the influence of live brucellosis vaccines（M5 and S2 strain）commonly used in China on the production of serum antibodies after immunization and growth of lambs，90 lambs of Hu sheep at one month old were randomly divided into three groups（M5 group，S2 group and the control group），M5 group was subcutaneously injected with M5 vaccine，S2 group was orally immunized with S2 vaccine，and the control group was intramuscularly injected with saline. All side effects after immunization were observed，and blood samples were collected before immunization and 7，14，21，28，90 and 120 days after immunization to detect antibodies by rose bengal plate agglutination test（RBT）followed by standard-tube agglutination test（SAT）for review. The lambs were weighed before immunization and 30，60，90 and 120 days after immunization to analyze and determine the influence of M5 and S2 on the lambs' growth. The results showed that more side effects could be caused by M5 as compared with S2；serum antibodies could be detected 7 days after immunization with M5，with a positive rate of 42.86%，reached a peak value（96.43%）after 14 days，then reduced to 29.63% after 120 days；for S2 vaccine，serum antibodies could also be detected 7 days after immunization，with a positive rate of 34.48%，reached to 93.10% after 14 days，then reduced to 27.59% after 120 days. The growth performance of the lambs at early stage could be delayed by M5 and S2 vaccine，especially M5 vaccine，for which，both the indexes of body weight and total weight gain were extremely significantly lower than those of the control group（P＜0.01）；while the indexes of the lambs only at 3 and 4 months old were extremely significantly lower than those of the control group（P＜0.01）when immunized with S2 vaccine，after that，the growth performance was gradually recovered. The development of a scientific and reasonable immunization plan for brucellosis in lambs was supported with data provided in the paper.