Telescopic connecting bar for trailers

The invention provides a telescopic connecting bar for trailers. The telescopic connecting bar comprises a connecting bar body. Two ends of the connecting bar body are both provided with hanger rings; at least one hanger ring is a moving hanger ring. Each moving hanger ring is provided with a hanger ring stop part. The end, close to the moving hanger rings, of the connecting bar body is provided with a connecting bar stop part hinged to a locking block. The end of the locking block is provided with a transition face which rotates with the locking block to match with the hanger ring stop parts so as to lock the moving hanger rings. The moving hanger rings can telescope in relation to the connecting bar body, so that the problem when parking space between an electric locomotive and a trailer is inaccurate, the need for manual hooking in the startup state of the electric locomotive causes potential major safety hazards is solved; the length of the connecting bar can be adjusted through telescoping the moving tra