Step S4: forming a plurality of cover plate alignment marks 14 on the base substrate 11, the plurality of cover plate alignment marks 14 are configured for aligning the display substrate including the pixel defining layer PDL, the light emitting elements 12, the encapsulation layer EPL, and the cover plate alignment marks 14 with the cover plate 30; the display panel includes a display region and a frame region located at a periphery of the display region. The frame region includes a dam glue 50 and an annular cutting region located on a side of the dam glue 50 away from the display region. An orthographic projection of at least one of the plurality of cover plate alignment marks 14 on the base substrate 11 is located between an orthographic projection of the dam glue on the base substrate 11 and display region, and the at least one of the plurality of cover plate alignment marks 14 is overlapped with the second inorganic encapsulation layer EPL2 in a direction perpendicular to the base substrate 11, and/or an orthographic projection of at least one of the plurality of cover plate alignment marks 14 on the base substrate 11 is located between the orthographic projection of the dam glue 50 on the base substrate 11 and cutting region.
        Step S5: forming an optical adhesive layer 20 on a side of the plurality of cover plate alignment marks 14 away from the base substrate 11.