Abstract:[Background] Brucellosis, caused by Brucella, is a significant zoonotic disease distributed and prevalent widely in many countries around the world. As an important disease, Brucellosis re-emerged in China in recent years, posing a great challenge to animal breeding industry and public health. Existing data about infection and epidemiology of Brucellosis in China are not comprehensive and systematic, due to the intensive breeding and big populations of animals in the country. [Objective] To better understand the prevalence of Brucellosis in dairy cows in China and to provide basis for the establishment of control measures and strategies. [Methods] Data were obtained and analysed based on the results of surveillance on 23 381 serum samples collected from dairy cows with miscarriage during 2013?2017. [Results] The positive rate of antibody against Brucella was 44.2%. The epidemic situation of Brucellosis in cows in 2015 was most severe, as evidenced by the findings that the highest levels of individual positive rate and group positive rate up to 55.3% and 93.5%, respectively, were detected. The positive rate of Brucellosis among the miscarriage herds in 5 provinces of the first-class Brucellosis epidemic areas ranged from 13.8% to 57.8%, and that in the second-class Brucellosis epidemic areas was between 54.4% and 86.9%. The incidence rate of Brucellosis in aborted dairy cows correlated well with the epidemic trend of human Brucellosis (r=0.806>0). Severe epidemic situation was observed in the second-class Brucellosis epidemic areas. [Conclusion] Our data presented here enhance our understanding of epidemiology of Brucellosis in China, and underscore the importance of nationwide monitoring of animal Brucellosis. In addition, prevention, accurate diagnosis, and elimination of the diseases on the farms should be strengthen in China.