A method for manufacturing a light emitting element includes: a GaN layer is formed on an AlN-deposited plain or patterned substrate, and the stress between different materials is changed and buffered through thermal treatment of annealing under H2 atmosphere or under H2 and NH3 mixed atmosphere, thus eliminating epitaxial wafer warp caused by such stress and improving epitaxial quality and light-emitting efficiency of the light-emitting element.