Objective:To analyze the clinical characteristics of asymptomatic infection of brucellosis, in order to provide reference for prevention and treatment of brucellosis.Methods:Retrospective analysis was used to collect the clinical data of patients with brucellosis asymptomatic infection and confirmed cases admitted to the 940th Hospital of Joint Logistics Support Force of Chinese PLA from 2017 to 2021, and the demography characteristics, clinical manifestations and laboratory test results were analyzed.Results:The results showed that a total of 18 cases of asymptomatic infection and 85 confirmed cases of brucellosis were included, and there was no statistically significant difference in age, gender, occupation and ethnicity distribution between the two groups ( F = 7.09, χ 2 = 0.74, 4.02, 0.55, P = 0.295, 0.785, 0.327, 1.000). The 18 cases of asymptomatic infection of brucellosis were found through screening in key populations, and no clinical symptoms or abnormal imaging signs were observed. The clinical symptoms of 85 confirmed cases were mainly muscle and joint pain, fever, sweating, fatigue, and low back pain; and the imaging manifestations were mainly arthritis, splenomegaly, and spondylitis. The median percentage of eosinophils (0.70%, 1.40%), percentage of basophils (3.05%, 0.40%), C-reactive protein (1.62, 4.62 mg/L), erythrocyte sedimentation rate (1.00, 11.00 mm/h), and antibody titer of serum agglutination test (1 ∶ 100, 1 ∶ 200) showed statistically significant differences between asymptomatic infection and confirmed cases of brucellosis ( Z = - 2.97, - 5.11, - 3.49, - 3.21, - 3.50, P = 0.003, 0.001, 0.001, 0.001, 0.007). Conclusions:There is a difference in the composition of granulocytes between asymptomatic infection and confirmed cases of brucellosis, and the level of inflammatory response indicators is lower than that of confirmed cases. Regular seroepidemiological surveys among key populations can help screen for asymptomatic infection of brucellosis.