The influence of the structure of azido oxetane polymers, i.e., the location, length and number of the pendant chains on their densities, enthalpies of formation, glass transition temperatures and mechanical properties of the polymers were investigated. The results show that the densities, enthalpies of formation and elastic moduli decrease monotonously as the number and length of the pendant chains increase. Glass transition temperatures has minimum values when there is one or two methane groups (-CH2) on the pendant chains. Moreover, the densities, elastic muduli and the enthalpies of formation increase with the introduction of azido groups. We found that the Tg of the polymers can be at best reduced by 17K without compromising the energetic or mechanical performances. This study reveals the structure-property relationships of the azido oxetane polymers and provides guidance on the principles of designing new energetic binders for explosives and rocket propellants.