Abstract: In order to solve the teeth crawling problem of driving wheel caused by smaller pitch of rubber caterpillar track in running system of unmanned caterpillar track vehicles, some researches were carried out. According to the meshing principle of synchronous belt, the meshing between driving wheel and caterpillar track was analyzed, and a method of reducing pitch by modifying the addendum circle diameter of the driving wheel was put forward, so that the pitches of driving wheel and track were controlled in sub-pitch meshing range to ensure smooth meshing. Then the feasibility of this method was verified. At the same time, it was proposed that the principle of equal-pitch meshing should be used in the design period. In order to prevent the failure of running system, the pitch of caterpillar track should be not smaller than 97% of the pitch of the driving wheel if there exists sub-pitch meshing during practical assembly.