Abstract: In order to significantly increase the molecular weight of the prepolymer by using a chain extender, in this paper, taking azide-terminated polyethylene oxide-tetrahydrofuran copolyether (AzTPET) and azido-terminated diethylene glycol (KL-1) as chain extenders seperatly respectively, a reaction with ATPET was arranged to prepare a polyethylene oxide-tetrahydrofuran copolyether polytriazole (PTPET) elastomer. Under the condition of maintaining the viscosity of the reaction system, some tests were carried out to analyze the influence of two chain extenders on mechanical and cross-linking network properties of the PTPET elastomer. The results show that the elongation of the PTPET elastomer synthesized by AzTPET can increase from 112% (no AzTPET) to 300% (add 40% AzTPET) at 20 ℃, while at 60 ℃, the elongation can increase from 70.1% (no AzTPET) to 153% (add 40% AzTPET). Correspondingly, the elongation of PTPET can increase from 112% (no KL-1) to 200% (add 50% KL-1) at 20 ℃, while at 60 ℃, the elongation can increase from 70.1% without KL-1 to 120% (add 50% KL-1), which can increase the elongation at break while maintaining stable tensile strength. It is obvious that the elongation at break of PTPET with both chain extenders can be greatly improved, while the tensile strength decreases with the first one. The tensile strength of the above PTPET samples can be increased with the increase of the amount of chain extender at −40 ℃. Both types of chain extenders can significantly increase the elongation at break of PTPET, but KL-1 in PTPET is better than AzTPET from the perspective of mechanical strength effect.