The invention discloses a corrosion-resistant external pressure axial compensator, comprising an inlet end pipe, an inlet end ring, connection pipes, an outer pipe, a corrugated pipe, an outlet end ring and an outlet end pipe, wherein the corrugated pipe is coaxially and fixedly connected with the connection pipes at two ends to form a corrugated pipe compensation structure; the outer pipe is coaxially and idly sleeved on the corrugated pipe compensation structure and is fixedly connected with the connection pipe of the corrugated pipe compensation structure at the outlet end by the outlet end ring in a sealing way; the corrugated pipe compensation structure is sleeved on the outlet end pipe; the connection pipe at the inlet end is fixedly connected with the port of the outlet end pipe in a sealing way; the inlet end pipe is fixedly connected with the port at the inlet end of the outer pipe by the inlet end ring in a sealing way; a corrosion-resistant composite layer is arranged on the outer wall of the corrugated pipe, and is perfectly a polytetrafluoroethylene composite layer. The corrosion-resistant composite layer is arranged on the outer wall of the corrugated pipe, the outer wall of the corrugated pipe is prevented from being corroded, and the service life of the compensator is effectively prolonged.