An initial display substrate comprising a product region and a to-be-processed region on periphery of the product region, the to-be-processed region comprising to-be-processed rounded corner regions at corners of the initial display substrate, each corner comprising major corner sides whose extension directions intersect, at least one to-be-processed rounded corner region comprising first positioning sub-region and two second positioning sub-regions, the major corner sides respectively defining edges of the second positioning sub-regions, the first positioning sub-region being between the second positioning sub-regions; first shielding blocks in the first positioning sub-region, each having arc shape protruding towards direction away from the product region, and the first shielding blocks being arranged in parallel at intervals; and second shielding blocks in each second positioning sub-region, a shape of the second shielding block is not exactly the same as that of the first shielding block.