The mechanical properties, physical crosslinking degree, crosslinking network structure integrity and tenacity of hydroxyl-terminated epoxy ethane/tetrahydrofuran random copolyether (PET)/polyfuctional isocyanate (N-100) binder films were analyzed by the uniaxial tensile test, infrared spectrum testing and equilibrium swelling methods. Results show that with increasing curing parameter (R), the crosslink density of PET/N-100 binder films increases gradually, the average molecular weight of chain segment between crosslink points decreases gradually, the maximum tensile strength and elastic modulus increases gradually, while the elongation at break decreases gradually. The crosslinking network structure integrity of PET/N-100 binder system is directly proportional to the ratio of hydrogen bonding, and is inversely proportional to the content of N-100. When the R value is 1.2, the correction factor of shear modulus of PET/N-100 binder films is the maximum, the crosslinking network structure is most complete, and the mechanical property is the better, the same as the tenacity of PET/N-100 binder film.