Hydroxyl-terminated polybutadiene(HTPB)/N100 reaction kinetics was investigated by method of the ratio of concentration and time. Matlab software was applied to calculate the reaction order and rate constant under different temperatures. The effects of various additions of catalyst on reaction rate,and the relationship between time and viscosity for HTPB/N100 reaction were studied. Results show that the reaction of HTPB/N100 belongs to the first order reaction,and activation energy is 70.57 kJ·mol^-1. With the increasing of catalyst proportion,the reaction rate constants increase,and the established exponential model for time-dependent of reaction system reveals their quantitative relationship.