The invention discloses a telescopic four-link joint transmission mechanism based on parallelogram, belonging to the technical field of robots. The telescopic four-link joint transmission mechanism comprises a first rigid body (1), a second rigid body (2), a third link (3) and a fourth link (4), wherein one end of the first rigid body (1) is hinged with one end of the second rigid body (2); one end of the third link (3) is hinged with the middle of the first rigid body (1); the other end of the third link (3) is hinged with one end of the fourth link (4); the other end of the fourth link (4) is connected with the middle of the second rigid body (2) by a hinge; four hinge joints form the parallelogram; the first rigid body (1) is provided with a fifth hinge joint (9); and a linear sliding pair is hinged between a third hinge point (7) and the fifth hinge joint (9). Compared with the pure telescopic four links, the mechanism has more stable motion output, improves the motion performanceof foot-type robot joints and provides a mechanism innovation and optimization mode for designing the foot-type robot joints with lightweight mechanism and efficient movement.