Abstract: This study takes Hulunbuir grassland as the research area, based on the grassland fire data in the region from 1990 to 2019, the Mann−Kendall mutation test and fire centroid analysis methods are used to study the changing trend, temporal and spatial distribution characteristics of grassland fires in the region. The research results show that in terms of time, 1998 was the sudden change node of the fire, the interannual changes of regional fires showed a downward trend as a whole, the fires occurred mainly in April, May and October, the fire time of the day mainly concentrated at 10 o'clock to 15 o'clock. In terms of space, fires in this area are mainly distributed in the west. The areas with higher fire density and grassland damage rate are mainly concentrated in Xinbarag Youqi and Xinbarag Zuoqi. The barycenter of mass of fire area and frequency of fire are showed planar distribution. The area barycenter as a whole shifts to high longitude and high latitude, and the frequency barycenter as a whole is obviously shifted to low longitude and low latitude; the distribution of major fires and particularly major fires are concentrated in Xinbarag Youqi, Chenbarag qi and Xinbarag Zuoqi. This research provides a certain decision-making reference for the fire prevention and control work of emergency and forestry management departments.