The invention discloses a novel large-span load-bearing prestress double-T plate construction method. The method comprises the steps that firstly, a double-T plate formwork structure is provided and comprises a shaped formwork frame and two ribbed beam end formworks, wherein double-T-shaped pouring channels are formed in the shaped formwork frame, and the two ribbed beam end formworks seal the two ends of the double-T-shaped pouring channels; each ribbed beam end formwork comprises a horizontal rib pressing plate, two vertical rib connecting plates and locating plates, wherein the two vertical rib connecting plates are arranged at the bottom of the horizontal rib pressing plate in a supporting mode, the locating plates are detachably connected to the bottoms of the vertical rib connecting plates, and each locating plate is provided with a plurality of tensioning holes used for penetration of reinforcing bars; secondly, long-line arrangement is conducted on the double-T plate formwork structure, and tensioning pedestals are arranged at the two ends of the double-T plate formwork structure; thirdly, the reinforcing bars penetrate through the tensioning holes in the locating plates, and reinforcing bar nets and embedded parts are arranged; fourthly, the reinforcing bars are subjected to prestress tension; fifthly, after the prestress of the reinforcing bars meets the strength requirement, concrete is poured into the double-T-shaped pouring channels; sixthly, after pouring is completed, concrete curing is conducted; seventhly, after curing is completed, the reinforcing bars are released, the double-T plate formwork structure is dismantled after the reinforcing bars are released, and then a double-T plate is made.