The invention discloses a prestress application device for a prestressed FRP-reinforced cylindrical structure. The prestress application device for the prestressed FRP-reinforced cylindrical structurecomprises a prestress device, a traction device and rail devices, wherein the prestress device is connected with the traction device through a connection rod; the prestress device comprises an FRP winding shaft; the connection rod is connected with the FRP winding shaft through a tension bar I; the FRP winding shaft is wound with FRP; the traction device comprises a transmission rod and a traction power source; the connection rod is connected with the transmission rod through a tension bar II; the transmission rod is driven to rotate by the traction power source; a transmission rod end gear is connected to the end part of the transmission rod; each rail device comprises a rack and a steel connection sheet; each rail device is semicircular, and the diameter of the rail device is matched with the outer diameter of a cylindrical structure to be reinforced; the two semicircular rail devices are connected through a bolt between the steel connection sheets to form a circular rail; and the transmission rod end gear is matched onto the racks. Prestress applied onto the FRP is uniform, so that the influence brought by friction between FRP and the reinforced structure (or the upper layer ofFRP) in an existing method is eliminated.