A composite solid propellant includes an oxidizer that supplies the necessary oxygen for combustion, a metal fuel powder, and a polymeric binder. Since the 1950s, a polyurethane network system has been widely used as a binder for solid rocket propellants. The urethane curing system which is moisture sensitive requires the elimination of moisture from both propellant ingredients and manufacturing environments. Furthermore, when ammonium dinitramide (ADN), the well-known substitute for ammonium perchlorate (AP), is used as the chlorine-free smokeless oxidizer, the polyurethane network system may suffer from the hydrolysis problem because of ADN’s highly hygroscopic properties. In this study, 1,2,3-triazole crosslinked polymers were synthesized as a new binder for solid rocket propellant systems by reacting the azide groups of the polymer with the ethynyl groups of a dipolarophile curing agent which is not sensitive to moisture and is free of side reaction during the synthesis process. All the mixtures were cured in an oven at 52°C for 7 days, and the curing reactivity of the products was analyzed using a Fourier transform-infrared (FTIR) spectrometer. The carbonyl group adjacent to the triple bond, which acts as an electron-withdrawing group, considerably accelerated the 1,3-dipolar cycloaddition reaction between the azide and ethynyl functional groups, affording rubbery materials. The modulus of the polymers increased whereas the elongation at the break decreased with increasing ratio of the crosslinker to the prepolymer, resulting in highly crosslinked polymers. The molecular weights between the crosslinking points and interaction parameters of the 1,2,3-triazole crosslinked polymers were determined from the swelling data, Flory-Rehner equation, and Mooney-Rivlin equation.