A method for printing on a shiny surface by a UV inkjet printer with transparency and high color density is described. Steps of the method include: (a) according to a conveying direction of a workpiece, dividing the workpiece with a reflective film into a plurality of continuous printing areas; (b) performing a printing operation on each printing area of the reflective film of the workpiece for at least three times; and (c) turning on a UV lamp at one side of an inkjet module when a final printing operation is performed on each printing area, to cure ink jetted from the inkjet module, thereby enabling the reflective film of the workpiece to still retain high shininess and high transparency after printing of the workpiece with a transparent reflective film surface is completed, and enabling a pattern printed thereon to have high color density.