The invention discloses a damping-force adjustable seat damper. The damping-force adjustable seat damper comprises an outer cylinder, an inner cylinder, a piston assembly, a hollow piston rod, an adjusting structure, a guide structure and a compression valve, wherein the guide structure comprises a guide base and a guide oil seal, the bottom of the guide base is provided with a non-return sealingfin, and the non-return sealing fin is in interference fit with the hollow piston rod; and the adjusting structure comprises an adjusting rod and an adjusting pushing fork, the surface of the front end of the adjusting rod is provided with a transverse guide groove, one end of the transverse guide groove is provided with a confluence hole, and the hollow piston rod is provided with a guide hole. Asafety relief valve structure is adopted by the compression valve, and the compression valve comprises a valve seat, a valve sleeve, a valve element, a valve clack and a reset spring, wherein the valve clack is provided with a pressure releasing channel, and the valve element is provided with at least one damping valve plate matched with the pressure releasing channel. According to the damping-force adjustable seat damper, up-and-down movement stability of the piston rod can be further guaranteed by means of the guide structure, the making process of the adjusting structure is simple, and theadjusting stability is good; and it can be guaranteed that the damper is stable and reliable to use by means of the compression valve, and the repair rate is decreased.