The invention discloses a method for grafting modification of a carbon fiber surface sizing agent through an alcohol amine solution, relates to a method for modifying the carbon fiber surface sizing agent, and aims to solve the technical problem of low interface bonding strength of conventional carbon fiber enhanced vinyl ester resin or unsaturated polyester resin composite material. The method comprises the following steps: 1, preparing an alcohol amine modifier solution; 2, carrying out carbon fiber surface modification. The method disclosed by the invention is simple and feasible; the carbon fiber surface sizing agent is directly subjected to chemical grafting, so that the own strength of carbon fiber cannot be damaged; the modified sizing agent can further achieve a carbon fiber protection effect. The interface shear strength and the comprehensive mechanical properties of a composite material prepared from the modified carbon fiber and unsaturated resin are all obviously improved.