Abstract: Tractor-trailer mobile robot is a complicated system, which is composed of a tractor and multiple trailers. The path planning problem of the system of this kind can not be solved using the path planning algorithm for single body car-like robot. This paper proposes the concept of band-path and gives the computation method of the band-path, which describes the characteristics of the path and the relationship between the path and restrictions. Based on those, an approach to the path planning for tractor-trailer mobile robot is supposed.