The invention provides a rack for testing the anti-sinking rigidity of the side surface of a vehicle body. The rack comprises a chassis, and a vertical frame and an upright post which are fixedly connected with the chassis, wherein transverse beam mounting plates are connected with the vertical frame; two ends of a transverse beam are connected with the vertical frame through the transverse beam mounting plates; an actuator mounting seat is connected with the transverse beam in manner of adjusting the relative position; the actuator mounting seat comprises a fixing seat, a movable seat and a hinge pin; the fixing seat is fixedly connected with the transverse beam; the fixing seat is hinged with one end of the movable seat and can be fixedly connected with the movable seat; the other end of the movable seat is fixedly connected with an actuator; the actuator is connected with a test head; a force sensor is arranged between the test head and the actuator; and a transverse beam transformation displacement sensor is arranged between the upright post and the transverse beam and is used for testing the deformation of the transverse beam during a rigidity test. The rack is simple in structure, easy to operate, high in adaptability and low in cost, and can effectively test the anti-sinking rigidity of the side surface of the vehicle body.