A method for patterning polycrystalline indium tin oxide by using a Gaussian laser beam focused on an amorphous indium tin oxide layer is disclosed to pattern the non-crystalline amorphous indium tin oxide layer and transfer part of the amorphous indium tin oxide layer into polycrystalline indium tin oxide while the remaining amorphous indium tin oxide layer is etched due to etching selectivity of an etching solution. The method comprises: providing a substrate with an amorphous indium tin oxide layer thereon on a carrier; transferring the amorphous indium tin oxide layer in a predetermined area into a polycrystalline indium tin oxide layer by emitting a Gaussian laser beam focused on the amorphous indium tin oxide layer in the predetermined area; and removing the remaining amorphous indium tin oxide layer on the substrate by an etching solution to form a patterned polycrystalline indium tin oxide layer.