A dual-screw linear actuator includes an inner push tube, an outer push tube, a first nut part, and a second nut part. The outer push tube is sheathed on the inner push tube and axially movable on the inner push tube; the first nut part is coupled to the outer push tube and screwed to an inner screw which has a coupling disposed at a front end of the inner screw; the second nut part is coupled to the inner push tube and screwed to an outer screw, and the outer screw is hollow, and the coupling is sleeved into the outer screw for an axial movement. The inner screw drives the outer screw to rotate, such that the first and second nut parts can synchronously push the inner and outer push tubes to extend or contract, so as to improve the stroke of extension or contraction.