Taking polyethylene glycol terephthalate copolyester (PETT) with 5% 2, 5-bis (hydroxymethyl) tetrahydrofuran (THFDM) mole fraction as raw material, copolyester PETT fiber was prepared by melt spinning method. The spinnability of PETT was discussed, and the impact of adding THFDM on the mechanical property, resilience performance, thermal shrinkage property and supramolecular structure of PETT fiber was explored. The result shows that compared with PET, PETT copolyester is subject to a wider control range of spinning temperature during spinning and has good spinnability. The PETT fiber prepared by low temperature spinning is high in breaking strength and low in elongation at break. However, the PETT fiber prepared by high temperature spinning is low in breaking strength and high in breaking elongation. The addition of THFDM has a certain effect on the mechanical property, thermal shrinkage property and supramolecular structure of PET fiber. Compared with PET fiber, the PETT orientation and crystallinity of fiber at the spinning temperature of 275℃ is reduced, while the elongation at break is increased. The breaking strength and elastic modulus are slightly reduced, and the boiling water shrinkage rate is slightly increased. Under a certain elongation condition, the elastic recovery rate of PETT fiber is higher than that of PET, and the resilience is improved, indicating that PETT copolyester with good spinnability is excellent in processing and molding.