In this study, the surfaces of the multi-walled carbon nanotubes (MWNTs) were treated by acrylic acid. The acid-treated MWNTs were functionalized and were characterized by Infrared spectroscopy. The MWNTs were opened at their ends by ultrasonic treating and UV irradiating. Different adding amounts of the opened MWNTs were filled to the epoxy resin, and their mechanical properties and thermal properties were measured by Instron, impact and differential scanning calorimeter (DSC), etc. The optimum adding amount of MWNTs to the epoxy resin is 2.0%, which is according to the parameters obtained from mechanical testing and T-g. The activation energy of the epoxy resin during curing can be calculated from infrared spectra according to the change of the epoxide band. The electrical conductivity of the MWNTs-filled composites was increased with proper (12.87%) amount of MWNTs adding, this is due to the networks constructed between MWNTs completely.