The correlation of diisocyanate structure with hydrogen bonding and microphase separation and further their influence on mechanical property was investigated in high soft segment (about 90 wt%) energetic poly(bis-azidomethyl oxetane/tetrahydrofuran) polyurethane binder. The hydrogen bonding analysis from Fourier transform infrared spectroscopy demonstrated that the limited intersegmental hydrogen bonding can occur in the hard domain, and small-angle X-ray scattering results also showed that the absence of high-order peaks in synthesized high soft segment polyurethanes. However, coplanar and symmetric diisocyanate and its inner benzene ring are favorable to ordered arrangement of hard segment, and further mircophase seperation enhance the tensile strength. POLYM. ENG. SCI., 59:724-729, 2019. (c) 2018 Society of Plastics Engineers