Epoxy resin was cured with a tertiary amine. The viscosity and dynamic mechanical properties during the curing reaction were measured by a cone-and-plate rheometer. A dual Arrhenius viscosity model was modified to predict the viscosity profile before gelation during the non-isothermal curing. The viscosity profile coincided with the experimental data. The activation energy of this system calculated using the modified model was 19.8 kcal mol-1 for the first region, and 17.3 kcal mol-1 for the second region. After gelation, the dynamic complex modulus was related to the reaction kinetics according to the rubber elasticity theory, and the activation energy was 15.3 kcal mol-1. Furthermore, the gelling point can be estimated from the rheological measurements.