The present invention relates to a method for forming a solder resist and a substrate for a package. According to one embodiment of the present invention, provided is the method for forming solder resist, which comprises the steps of: forming a first solder resist inner region by primarily coating, exposing, and developing a solder resist on a substrate on which a circuit pattern including an outer POP pad for mounting an upper package thereon and an inner chip pad for mounting an inner chip is formed, wherein the first solder resist inner region is formed on an inner region of the substrate on which an inner circuit pattern including the chip pad is formed; forming a plugged SR region which does not expose the substrate while exposing the entire upper surface of the chip pad by performing a laser ablation process on the first solder resist inner region; changing a surface roughness by performing a desmear process on a surface of the first solder resist inner region in which the plugged SR region is formed; and forming a second solder resist SMD region by secondarily coating, exposing, and developing the solder resist on the substrate after the desmear process, wherein the second solder resist SMD region covers an edge of the POP pad. Further, a substrate for a package is provided.