Abstract: In order to investigate the influence of walking speed, ground slope and ground friction coefficient on the lateral stability of tractor chassis, this study firstly establishes the tractor dynamics model, considers two types of tractor instability, which are overturning and skidding caused by tractor chassis instability, and determines the stability index for each case, selects the MITSUBISHI MT-2501D tractor for test and analysis. Analysis, the results show that the walking speed and ground slope have a significant negative correlation effect on all stability indexes（P ＜ 0.05）, the stability of this tractor is more affected by tractor skidding than overturning. Therefore, in order to improve the overall stability of this tractor chassis, priority should be given to improving the tractor stability index derived from tractor skid dynamics. The results of the study provide new research ideas and technical references for improving the stability of agricultural tractors in field operation.