A method of forming a biomass photosensitive material is provided, which includes (1) polymerizing (a) itaconic anhydride and (b) acrylate to form a copolymer, and (2) mixing the copolymer and (c) monomer with a single hydroxy group and a carbon-carbon double bond for a ring-opening addition reaction, wherein the (a) itaconic anhydride and the single hydroxy group of the (c) monomer with the single hydroxy group and the carbon-carbon double bond are reacted in the ring-opening addition reaction.