Disclosed are a coupler buffer connector for a rail vehicle and a buffer connecting system using the same, the coupler buffer connector comprising a mounting seat (1), at least two energy absorbing components (2), a traction rod (3) and a locking member (4), and further comprising a rotary shaft cylinder (5) mounted inside a first mounting hole (1-1) of the mounting seat (1) and restricting the axial movement of the rotary shaft cylinder (5) inside the first mounting hole (1-1) by means of a cutting component (6), wherein the rotary shaft cylinder (5) has a second mounting hole (5-1), the second mounting hole (5-1) is internally provided with a baffle board (5-3) approximately perpendicular to the axial direction, and the traction rod (3) movably and axially passes through a baffle hole (5-3-1) of the baffle board (5-3); two sides of the baffle board (5-3) are respectively provided with at least one energy-absorbing component (2) sheathed on the traction rod (3); and the rotary shaft cylinder (5) is provided with a guiding groove (5-4), a guiding pin (18) fixed relative to the mounting seat (1) at least partly extends into the guiding groove (5-4), and when the coupler buffer connector is overloaded, the cutting component (6) is approximately axially cut off and enables at least the traction rod (3) to move the rotary shaft cylinder (5) in a guided manner by means of the guiding groove (5-4). The coupler buffer connector has a simple overload detaching structure, and will not be offset or jammed during the detaching process, and the overall structure is simple and compact.