This paper discusses the design method of a self-propelled catheter with thin diameter of 2.6mm, aimed for moving and steering in the bronchi. As the basic configuration, the proposed catheter is composed of an inner tube and McKibben artificial muscles. It can propel by generating travelling waves by a single supply line driven by pneumatics. Since the inner tube equips with orifices of different size, several McKibben chambers can deform with the time delay. We also propose the method to steer the direction at the branch pipe, whose angle can be adjusted by PWM control of pressuring. Besides, we also introduce the design method of how to deal with the pipes with different diameter. The validity of these proposed methods are verified by the prototype through the experiments in the bronchial model.