The tractor-trailer mobile robot (TTMR) is composed of a tractor and multiple trailers. It belongs to a typical nonholonomic, underactuated system. The general control theory can hardly be applied to this system. Because of the multi-body tractor-trailer mobile robot existence, the moving trajectory control is very complicated, especially backward path control becomes a difficult problem for this kind of robot control. This paper takes parking trajectory generation for example, makes tentativeness on tractor-trailer mobile robot to generate the trajectory based on Repeatedly Direct Kinematics (RDK) method. The feasible forward and backward trajectory generations algorithm for tractor-trailer mobile robot are proposed. The design complexity and existing singularity for tractor-trailer mobile robot system are solved. Simulations show the effectiveness of the proposed method.