2,2′‐Dithiobisethanamine (cystamine), an aliphatic diamine containing exchangeable disulfide bonds, was used as the curing agent for epoxy resin. The dynamic curing kinetics and thermal stability of the epoxy/cystamine system were investigated by DSC and TGA analysis. Applied the Málek method, the Sestak–Berggren autocatalytic equation was selected to describe the cure kinetics of the epoxy/cystamine system. The results showed that the Šesták– Berggren equation is in good agreement with the experimental data. The activation energy of the curing reaction was 56.2 and 53.6 kJ mol −1, respectively, calculated by Kissinger and KAS models. Also, the glass transition temperature for the epoxy/cystamine system was slightly than that of the commonly used epoxy‐diamine systems. Moreover, the thermal degradation of the cured epoxy/cystamine network was observed at temperatures above 283°C. Further, the results obtained from the epoxy/cystamine system were compared with those obtained from the epoxy/diethylenetriamine system. All the above results suggest that cystamine has the potential to be used as the curing agent for epoxy systems.