Gram stain was devised empirically by Christian Gram, a Danish physician, in 1884. Gram positive cell wall contain thick layer of peptidoglycan with numerous teichoic acid cross linking, after Gram stain, the complex of crystal violet and iodine firmly remained within the cell wall, it is not easy to remove by decolorize solution and continued to show a purple. On this basis, it’s formation of a Gram stain reagents. The main difference between Auto stainer reagent and traditional Gram stain is the decolorize solution and counterstain merged into Acetone Fuchsin staining solution.