This disclosure relates to a peeling method of a flexible substrate, and belongs to the technical field of flexible display. The method comprises the steps of: (a) forming a flexible substrate on a base substrate, wherein the flexible substrate has a plane area less than that of the base substrate; (b) adhering a protective film on the base substrate formed with the flexible substrate by an ultraviolet viscosity-reducing adhesive, wherein the plane area of the flexible substrate is less than that of the protective film, and the protective film is further adhered to the base substrate by the ultraviolet viscosity-reducing adhesive; (c) irradiating a region on the base substrate covered by the protective film through the base substrate with an ultraviolet light; and (d) peeling the protective film and the flexible substrate from the base substrate after the irradiation with an ultraviolet light is completed.