Cable pre-tensioning device for main cable of suspension bridge and using method of cable pre-tensioning device

The invention discloses a cable pre-tensioning device for a main cable of a suspension bridge and a using method of the cable pre-tensioning device. The cable pre-tensioning device for the main cableof the suspension bridge comprises two supporting longitudinal beams, semi-circular channel steel, cable pre-tighteners, two circular handles, two stainless steel pull rods, adjustable bolts, a traveling crane and movable limiting blocks, wherein the supporting longitudinal beams are parallelly arranged on two sides of the main cable; the bottoms of the supporting longitudinal beams are connectedonto the traveling crane; the semi-circular channel steel is fixedly connected onto the supporting longitudinal beams; the inner side of the semi-circular channel steel clings to the main cable; the stainless steel pull rods are correspondingly arranged above and below the main cable; both ends of the stainless steel pull rods are fixedly connected with the supporting longitudinal beams on both sides of the main cable corr