The performance of epoxy thermosets was greatly influenced by the curing agent and curing temperature. It was known that epoxy thermosets cured under high temperature would have high normal forces which could cause fracture of the structure and then decrease the mechanical properties of the material. It was accepted that epoxy curing system should be cured under low temperature with the thermosets had the same properties as those cured under high temperature. It was important to choose proper curing agent to reach the above goal. Latent epoxy curing agent whose main component was the hyperbranched polyester (HBP) with tertiary amine as the end group was prepared and was used to diglycidyl ether of bisphenol A (DGEBA) in this work. The properties such as tensile intensity, bending intensity, impact resistance and dynamic mechanic properties of the resulting epoxy thermosets were evaluated. It was found that the resulting epoxy thermosets cured under low temperature had better mechanical properties than those cured under high temperature. The latent epoxy curing agent whose main component was the hyperbranched polyester with tertiary amine as the end group was adaptive to be used in the epoxy base of composite.