The invention belongs to the field of electronic device preparation processes, and discloses a preparation method of a patterned mask. The method comprises the following steps of 1), depositing a light-absorbing material layer on the first surface of a transparent substrate and performing patterning; 2), performing spin-coating on the second surface of the transparent substrate for obtaining a polymer material layer; and 3), irradiating laser on the first surface of the transparent substrate, wherein in the area which is covered by the light-absorbing material on the substrate, laser energy does not reach a polymer material ablation threshold, the polymer is kept; and the polymer in the area which is not covered by the light-absorbing material on the transparent substrate is ablated by the laser, and patterning is realized after the polymer material layer is ablated. Furthermore the shape of the pattern is same with that of the light-absorbing material deposited on the first surface of the transparent substrate, thereby forming the patterned mask. The preparation method can realize interface adhesion strength regulation after laser lift-off. Through controlling the interface adhesion strength after laser lift-off, a large-area flexible ultrathin device still adheres on a rigid substrate after laser lift-off.