A novel waterborne epoxy curing agent was prepared using 3-glycidoxypropyl trimethoxysilane (GPTMS) as a termination agent of adduct, which was synthesized by triethylene tetramine (TETA) and liquid epoxy resin (E-51). The effects of the reaction temperature and time on the synthesis process were investigated experimentally. The particle size and the distribution of water dispersion of the curing agent were measured by dynamic light scattering (DLS). The structure of the products was characterized by Fourier transform infrared spectrometer (FTIR) and H-1-nuclear magnetic resonance (H-1 NMR). The properties of the synthesized curing agent and the epoxy resin film cured by it were also measured. The results showed that the appropriate temperature for the synthesis of adduct was at 65-75 degrees C and the reaction time was 4-5h, and that the suitable reaction temperature of curing agent synthesis was 75-85 degrees C and the reaction time was 3-4h. When the mass ratios of GPTMS and acetic acid were 3%-5% and 5%-10% respectively, the hardness, water resistance and adhesion of the cured film were improved significantly.