The present application provides a method for improving colour difference of an LED display screen, comprising: drilling and polishing circuit surfaces of a plurality of LED substrates; performing screen printing on the circuit surfaces of the plurality of LED substrates, and performing oil skimming on a mesh screen during the screen printing every other preset printing cycle in such a way that an ink on the mesh screen has a viscosity within a predetermined viscosity range; performing an exposure setting process on the plurality of LED substrates that have been screen printed to obtain a plurality of LED printed circuit boards; and finally assembling the plurality of LED printed circuit boards to form an LED display screen.