The effects of salt, molecular weight and viscosity, and mass ratio on the apparent activation energy of the cross-linking reaction of epoxy resins and protein hydrolysate were studied by nonisothermal differential scanning calorimetry. The Kissinger equation, the model-free isoconversional method, and the autocatalytic model were used to analyze the kinetic data. The presence of salts contributed to an increase in the apparent activation energy. The curing of epoxy resins with lower molecular weight protein hydrolysates was found to have lower activation energy and order of reaction. An increase in the concentration of curing groups resulted in a small increase in the order of reaction. The activation energy of curing bisphenol A diglycidyl ether (DGEBA), with viscosity 500-700 cP, was found to be significantly higher than the curing activation energy of polypropylene glycol diglycidyl ether (PPGDE), which has a viscosity of 50 cP.