The invention discloses a mechano-chemical method for preparing thin-layer paper. According to the invention, paper pulp and chemical auxiliary agents are ground into fibrillated pulp; and through processes such as dehydration, shaping, pressing, drying, and the like, the thin-layer paper is obtained. The method has the advantages of simple operation process, low energy consumption, and high production efficiency. With the mechano-chemical method thin-layer paper preparation method, a synergistic effect of mechanical force, heat power and chemical power can be fully utilized, reaction activation energy can be reduced, and fiber fibrillation and thinning can be promoted. Mechanical strength is good, and thin-layer paper strength can be improved.