[Objective] In order to explore the dynamical changes of antibodies after being immunized with brucellosis vaccine of S2 strain in adult sheep.[Methods] Vaccination experiments were conducted by three different methods：perfusion of 10 billion bacteria，perfusion of 20 billion bacteria，and intramuscular injection of 5 billion bacteria. Serum samples were collected in different time-points before and after vaccination，the antibodies were detected by Rose Bengal plate agglutination test（RBT）and tube agglutination test（SAT）. [Results] The antibody level after intramuscular injection rose faster than the rest，it rose up to the highest level on 10th day after immunization，then declined rapidly and descent speed became slow after 90 days. The positive rates of RBT and SAT were 63.2% and 84.2% on 180th day after immunization，and the average agglutination titer was 1:178.9. On the other side，the antibodies of oral groups reached peak on 20th day after immunization，then decreased，the minimum level appeared on the 90th and 180th day，respectively. Then they increased slightly and waved at the low level. On the 180th day，the positive rates of both two oral groups detected by RBT fell to 0%，while that by SAT dropped to 40.9% and 23.1%，respectively. [conclusion]The 6 months after oral immunization with brucellosis live vaccine of S2 strain in sheep flock，RBT could be used in preliminary screening of brucellosis inspection and quarantine.