Abstract: Principle, advantages and disadvantages of the current three fromats of catenary rigid flexible transition section are expounded, and the required conditions of setting rigid flexible transition on metro inlet/outlet line small\|radius curve are demonstrated. Two hanging ways at the rigid flexible transition section, namely, vertical suspension method and cantilever suspension method are compared. It is recommended to use vertical suspension to ensure the interface of contact line parallel to pantograph for small\|radius curve line. It is suggested to do lofting according to the actual line conditions during design, in order to carry out plane and facade layout of catenary rigid flexible transition section, of which detailed design steps and precautions are listed.