Abstract: A nail painting machine, a cartridge for painting human nails is provided, and a method for painting human nails using a nail polish machine containing a nail polish cartridge therein is provided. The nail painting machine comprising a casing, the casing having an opening-closing means configured to open the casing to access a cartridge receiving portion and to close the casing to enclose the cartridge receiving portion; a positioning assembly disposed inside the casing including at least one motor, wherein the cartridge receiving portion is rotatably attached to the positioning assembly; and an operation assembly disposed inside of the casing having at least one positioning detector, and an ECU configured to communicate with the positioning assembly, and at least one positioning detector.