The content distribution of chemical groups and the kinetics of curing process in the micro-region interfaces of nitrate ester plasticized polyether (NEPE) based propellant/hydroxyl-terminated polybutadiene (HTPB) based liner were studied by in-situ diffuse reflection FT-IR spectroscopy. During the curing process, the content of -NCO groups showed little increase in the liner region toward the interface. It rises quickly through the interface layer and is then stable in the region of the propellant layer, while the content of -NH groups gradually increases from liner to propellant. In the micro-region between liner and propellant, the -C=O decreases rapidly through interface and then has a slight increase in the propellant region. Migration of nitrate esters appears at the interface of the NEPE propellant/liner at early period of curing, and -O-NO2 decreases from propellant to liner in the bonding interface micro-region. A study of curing kinetics indicates that the second-order reaction model can describe the curing reaction in the bonding interface at the early stage of curing process. The order of apparent curing reaction rate constant (k) of liner (L point), intermediate point (I point) and propellant (P point) in the interface micron-region is kL > kI > kP at the same curing temperature. The apparent reaction activation energy (E-a) at L, I, and P points are 39.96, 81.49, and 62.51 kJ mol(-1), respectively, based on the Arrhenius equation.