To understand the curing process of hydroxy-terminated polybutadiene(HTPB)/isophorone diisocyanate(IPDI) binder system under the conditions of different catalysts [dibutyltin dilaurate(DBTDL), ferric acetylacetonate(FeAA), tin (ii) ethyethylhexanoate(TECH), diazabicyclooctane(DABCO), triphenylbismuth(TPB) and nano zinc oxide (nano-ZnO)], the relationship of viscosity vs. time for HTPB/IPDI system under the action of different catalysts at 45 ℃ was studied by viscosity method, and the changes in curing reaction rate were discussed. Results show that the rheological reaction rate constant for HTPB/IPDI system without catalyst and under the action of different catalysts at 45 ℃ is determined as k_blank=0.002, k_DBTDL=0.045, k_FeAA=0.0439, k_TECH=0.0335, k_DABCO=0.0051, k_TPB=0.0036 and k_nano-ZnO=0.0034. The effect of different catalysts on the curing reaction rate of HTPB/IPDI binder system decreases in the order of DBTDL > FeAA > TECH > DABCO > TPB > nano-ZnO. In the HTPB/IPDI system, when DBTDL, FeAA, TECH, DABCO, TPB and nano-ZnO are used as catalyst, the pot-life of the binder system is 0.3, 0.7, 1.9, 6.7, 16, 18 h, respectively. Through the change situation analyses of the pot life and the reacon rate constant k for sulrry during the curing process, considering that TPB is more suitable to be used as the curing catalyst of HTPB/IPDI system. The trend of the logarithm of viscosity increases with time reveals the phenomenon of two defined stages, fast early stage and slow later period, and deviation from the bottom right of graph line. The main reason for this phenomenon is due to the obvious reactive differences of NCO groups in IPDI. Science the steric effect of the methyl group and the cyclohexane ring, the reactivity of prim NCO group is significantly lower than the secondary NCO group.