Trial-and-error approaches for experimentally designing and optimizing the polymer matrix for advanced composites are time-consuming and expensive. The simulation for curing behavior and structure property relationships of epoxy resins can provide a guideline for designing resin matrix which will possess desirable properties. So far there are few reports in which the accuracy of the molecular simulation for the different amine-epoxy systems are addressed. In this paper, an atomistic modeling technique was used to theoretically investigate the curing and thermal transition behavior of two epoxy resin matrices containing amine curing agent with different chemical structures i.e. diaminodiphenyl methane (DDM)/diglycidyl-4,5-epoxycyclohexane-1,2-dicarboxylate (TDE85) and diaminodiphenyl sulfone (DDS)/TDE85 to give help for designing high heat-resistant epoxy matrix. The simulated results successfully predicted that the reaction process was catalyzed in the early stage of the curing and the slight modification in the diamine structure resulted in significant change in the curing and glass transition behavior of epoxy resin. As the bridging group of diamine changed from methylene to sulphone, the reactivity of diamine toward epoxy declined and the glass transition temperature increased from about 190 C to about 230 C. This simulated method presented a good agreement with experimental data, and can be used to design and predict high performance resin matrix for advanced composites. (C) 2013 Elsevier Ltd. All rights reserved.