Provided are a scattering layer and a method for preparing the same, and an organic light-emitting diode display device prepared thereby. The scattering layer is formed by coating a block copolymer solution of a polybutadiene-polystyrene onto a substrate to form a film, and then subjecting the film to treatment of curing and annealing. The resulting scattering layer includes a nanoscale polystyrene microsphere structure obtained by self-assembling polystyrene and polybutadiene.