The invention discloses a self-propelled distribution line inspection device. The self-propelled distribution line inspection device comprises a driving roller, a driven roller, a steering engine, a stepping speed reducing motor, a belt transmission mechanism, a bidirectional locking mechanism, a control box, a machine frame and an insulating rod joint, wherein the bidirectional locking mechanismcomprises a connecting rod and a lock plate, wherein the lock plate is pivoted to the machine frame, and the connecting rod is connected between the lock plate and a rocker arm of the steering engine;a lock shaft is arranged at one end of the lock plate, and a lock opening is formed in the other end of the lock plate; the machine frame comprises a bottom plate and a square sleeve joint, wherein the square sleeve joint is connected with the insulating rod joint in an inserted mode; and the square sleeve joint and the insulating rod joint are provided with locking sliding grooves which are overlapped with each other, wherein the lock plate has two locking states for being selectively locked with one of the insulating rod joint and the roller shaft of the driving roller. In the line inspection device, the insulating rod joint has the characteristics of being reliable in connection and rapid in separation.