Abstract: Torsional Braid Analysis (TBA) is used here to investigate the apparent kinetics of the curing process in the system of hydroxy-termi-nated polybutadiene (HTPB) and tolylene diisocyanate(TDI). The apparent activation energy is obtained. The results are also verified by viscosity measurement and infrared spectroscopy. It is suggested that TBAcan be used as a significant and successful method for investigating the cure reaction of liquid rubber.