Curing processes of HTPB/TDI and Al/HTPB/TDI composites were measured by non-isothermal differential heating calorimetry at different scanning rates. Results show that the values of apparent activation energy,reaction order and frequency factor of HTPB/TDI system are 51.826 kJ·mol^-1,0.926,2.412×105 min^-1,respectively. After adding aluminum powder,the peak temperature of the curing process is decreased. The values of apparent activation energy,reaction order and frequency factor are increased to be 76.402 kJ·mol^-1,0.944,2.53×108 min^-1,respectively. The curing reaction mechanism of HTPB/TDI meets Avrami-Erofeev Equation G(α)=［-ln(1-α)］ⁿ. The addition of aluminum powder into HTPB/TDI curing system only makes little change on index n. The curing reaction of HTPB/TDI can be accelerated by aluminum powder for the initial 18% of reaction extent and aluminum powder slows down the curing reaction for the latter 82% of reaction extent.