The invention discloses a thermosetting artificial board starch adhesive and a preparation method thereof, and belongs to the technical field of adhesive preparation. Starch is used as a main raw material, and after acidolysis, a semi-continuous seeded emulsion polymerization method is adopted for preparation. By accurately controlling the pre-gelatinization temperature, the initiator adding time,the crosslinking monomer adding amount, the crosslinking monomer dripping speed and the crosslinking monomer dispersion liquid concentration, the reaction degree of crosslinking monomers is reasonably controlled, and the step of dripping comonomers is omitted. Meanwhile, the reaction time is greatly shortened, the use amount of petroleum monomers is reduced, complex reaction steps are simplified,the proportion of starch accounting for the total solid content is increased to 75% or above from 40%, and the cost of the starch adhesive is reduced. The adhesive disclosed by the invention is goodin water resistance and strong in cohesion, various properties of the manufactured artificial board exceed the standard of class II artificial boards, and the adhesive is suitable for mass productionand is widely applied to adhesion of hot-pressed wood decorations, artificial boards and plywood.