Abstract: ased on 863-512 task,this papet discusses the action planning technology on an unmanned op- erated track-laying mobile robot from its motion characteritics,motion description,motion control, and mo-tion plan respectivelly,Firstly,it analizes theorectially the internal motion mechanism of atrack-laying mobile robot,and points out the differences from a wheel vehicle in its motion characteritics,especially in steering. then it concludes out the nearly uncontrollbility of motion angular speed and the inaccuracy of pivoting angle on the vehicle and some rules abided by action planning.On the longitudinal motion control,one speed model is discussed,a new scheme of speed measure and control is proposed which proved more simple,more reliable,and more accurate than general ones. On the lateral motion,the steering control is perfectly solved by adopt- ing the fusion of a PWM-like method and a FM-like method.The above methods and technologies kave been successfully applied to an unmanned operated track vehicle,Some experiments are given.