Abstract: In order to solve the problem that some pests and diseases can not be found in time during the forest inspection, resulting in economic losses, and the complex road conditions in the forest lead to frequent injury of forest patrollers, this paper proposes a forest pests and diseases tree marking vehicle, which adopts the four-track walking mode of hollow shaft and solid axial cooperation, so that the vehicle can change the position of the marking vehicle by changing the swing angle of the track while completing the front and back movement, It has greatly improved the passing ability and obstacle surmounting ability of the marked vehicle. In this paper, the obstacle surmounting model is established, and the relationship between the parameters of the tree marker vehicle and the obstacle surmounting height is obtained. Through establishing the multi-body dynamics model of the tree marker vehicle for forest diseases and insect pests, the simulation experiments of double-side obstacle crossing and single-side obstacle crossing were carried out, and the transformation laws of the swing arm moment and swing arm angle during obstacle crossing were obtained. The simulation prototype was trial-produced for test, and the results showed that the forest pest and disease marking vehicle could complete the marking of pest and disease trees by adjusting its posture through the obstacles in the forest.