The invention disclosess a segmented copolymer of poly-p-dioxanone/polyethylene glycol terephthalate; the copolymer is characterized of being prepared by dropping coupling agent diisocyanates in a fused mass formed by melting modified low-melting polyethylene glycol terephthalate pre-polymers whose melting point is not greater than 210 degrees centigrade, the limiting viscosity number is not greater than 1.5 dL/g and both ends are hydroxyl groups, and poly-p-dioxanone whose the limiting viscosity number is not greater than 0.8 dL/g and both ends are hydroxyl groups at a certain temperature, the limiting viscosity number of the copolymer is 0.5 to 2.5 dL/g, and the melting point is at 100 to 180 degrees centigrade. The invention further discloses a method for preparing the copolymer. The segmented copolymer discloseed by the invention has high molecular weight and excellent thermal stability and machinability, and has excellent biodegradability of poly-p-dioxanone, which lays the foundation for the materials as commercial macromolecular material. The invention is simple in process and easy to control the reaction, thereby realizing large-scale and continuous industrial production.