Objective To understand the epidemiological characteristics and spatiotemporal distribution of human brucellosis in Inner Mongolia Autonomous Region（Inner Mongolia） from 2004 to 2023, and provide reference the development of targeted surveillance and prevention strategies.

Methods The incidence data of human brucellosis in Inner Mongolia from 2004 to 2023 were collected from China’s National Notifiable Disease Reporting System for a statistical analysis with software Excel 2021, and SaTScan 10.1.

Results From 2004 to 2023, a total of 249 407 cases of human brucellosis were reported in Inner Mongolia, with an annual average of 12 470 cases. The annual incidence rate varied from 18.27/100000 to 88.62/100000, with average annual incidence rate of 48.77/100000. The incidence rate increased from 18.27/100000 in 2004 (4 356 cases) to 68.34/100000 in 2023 (16 409 cases), indicating a serious epidemic situation of human brucellosis. From 2004 to 2023, 5 leagues (prefecture) in eastern Inner Mongolia reported the highest case count, accounting for 64.49% of the total (160 848 cases). The epidemiological characteristics at the county level showed significant changes during the period from 2004 to 2023, with both the number of affected counties and the incidence rates increasing. The number of banners (counties/districts) reporting cases increased from 57 in 2004 to 105 in 2021, and the number of counties with incidence rate higher than 50.00/100000 in 2004 increased from 16 to 68 in 2021, indicating a serious epidemic situation of human brucellosis in Inner Mongolia year by year. The analysis on spatiotemporal clustering showed that a total of 5 high-risk clustering areas were detected in 105 banners (county/district) in Inner Mongolia from 2004 to 2023, in which 57 (54.28%) were high-risk clustering areas, with the high-risk areas shifting from eastern to western regions.

Conclusion The incidence of human brucellosis in Inner Mongolia showed an increasing trend, and the spatiotemporal distribution of high-risk areas showed changes. Targeted intervention strategies should be taken to control the further spread of human brucellosis.