The invention relates to a two-stage air cock type buffer which comprises an outer barrel, a core rod, a second-stage piston rod and a first-stage piston rod, wherein a groove for inserting one end of the core rod is formed in the outer barrel, the other end of the core rod is mounted on an oil distribution disc, and the first-stage piston rod sleeves the oil distribution disc in an empty manner; meanwhile, a boss for driving the second-stage piston rod to compress is arranged on the outer side of one end of the first-stage piston rod, the second-stage piston rod in lap joint with the lower end of the outer barrel extends out of the outer barrel, limiting pieces are separately arranged on two sides of the inner portion of the second-stage piston rod for limiting extrusion of the first-stage piston rod, and the limiting pieces are far away from the boss at one end of the first-stage piston rod, hydraulic oil passes through the inner portions of the second-stage piston rod, the first-stage piston rod and the outer barrel through the oil distribution disc, and an air cavity is formed in the upper side of the outer barrel. On the premise of requiring a buffer property and being equal in compression strokes in first and second stages, compared with a conventional two-stage air cock type buffer, the structural length is greatly shortened, the structural weight is effectively reduced, and the collecting space of an undercarriage system is reduced.