The invention relates to a loading and unloading telescopic rail used for finishing connection between a railway platform and a railway box car carriage. The loading and unloading telescopic rail comprises a fixed rail used for fixing and at least two movable rails which are movably connected with the fixed rail and are capable of finishing telescopic operation. The extending directions of the fixed rail and the movable rails are the same and perpendicular to the longitudinal extending direction of the railway box car carriage. The fixed rail and the movable rails are located in the same plane, and the plane is parallel to the horizontal plane. The loading and unloading telescopic rail can make a loading and unloading forklift sub-machine operate at a high speed on the smooth rail, the influences on the loading and unloading forklift sub-machine by a gap and the height difference between the railway platform and the railway box car carriage are eliminated to the great extent, the running efficiency of a whole railway box car loading and unloading system is improved, and the problem that a carriage bottom board is likely to become uneven after a loading and unloading system in the prior art is used for a long time is solved as well.