The curing mechanism of bisphenol-A diglycidyl ether type epoxy resin (DGEBA) cured with 2-ethyl-4-methylimidazole(EMI-2，4)，and the curing charac-teristics，kinetic and reactivities of DGEBA，diglyddyl ester and aliphatic cyclo type epoxy resin (TDE-85) cured with EMI-2，4 have been studied bv DSC，FTIR in this paper．The results of DGEBA cured with EMI-2，4 show that the whole curing mechanism can be separated into two stages．The first stage was addi-tion，the second stage was catalytic-polymerization．The whole curing of TDE-85 epoxy resin cured with EMI-2，4 proceed in two stages as well．The first stage mainly was addition and catalytic-polymerization of diglycidyl ester type epoxy group，the second stage mainly was addition of aliphatic cydo epoxy group．The apparent activation energy in the first stage of various epoxy resin cured system is lower than that in the second stage．It was found that in the co-curing system of reactivity of TDE-85 with DGEBA tVpe eooxy resin cured with EMI-2，4 is higher than that of TDE-85 epoxy resin．