The invention belongs to the field of papermaking additives, and particularly relates to a surface glue reinforcing agent and a preparation method thereof. The surface glue reinforcing agent is prepared from polyvinyl alcohol, N-methylol acrylamide, hydrophilic monomers, hydrophobic monomers, cationic monomers, an initiating agent, a crosslinking agent, an emulsifying agent and water. The molecules of the surface glue reinforcing agent contain a large quantity of functional groups such as hydroxyl and carboxyl, the surface glue reinforcing agent can strongly adhere to fibers, and the bonding strength among fibers can be improved; meanwhile, the surface glue reinforcing agent has the function of forming a net structure through self-crosslinking, the acting force between the reinforcing agent and other reinforcing agents and between the reinforcing agent and fibers and filler is increased, and the acting effect of the reinforcing agent is improved; due to the good film forming property of the surface glue reinforcing agent, migration of surface glue to the interior of paper can be reduced, the surface strength of paper can be improved, and the linting and dusting phenomenon can be avoided. By means of the preparation method, the defect that the strength of body paper is reduced in a body paper highly-filling technology or a method of adopting a staple fiber raw material (like secondary fibers) in a high proportion can be overcome, the ash content of paper can be improved, and cost can be reduced.