A high-efficiency surface sizing agent is mainly made from the following components by mass percent: 10-18% of an alkyl ketene dimmer, 10-18% of a graft copolymer of starch and acrylamide, 8-16% of polyamine resin, 3-10% of quaternary ammonium salt of trimethyl ammonium chloride and 45-65% of water. The surface sizing agent has the advantages of excellent sizing effect, good film forming property, wide application range and environmental protection. Using the surface sizing agent, the surface sizing agent is easily kept on a surface of a paper sheet, which obviously improves indexes of the paper sheet after sizing, such as surface strength, smoothness, Cobb value, printability and the like, and eliminates phenomena such as linting, dusting, pasting and the like during a finished paper printing process. And, the surface sizing agent can greatly reduce sizing procedures of paper making and requirement for a slurry clarifying system, thus the surface sizing agent can completely replace internal sizing to reduce sizing cost on the paper sheet.