Leather dyes refer to dyes with an affinity to leather and for leather coloring. Based on solvent types, it can be divided into two categories: non-water-soluble dyes and water-soluble dyes. Non-water-soluble dye comprises: sulfur dyes soluble in aqueous solution of sulfide; fat-soluble oil-soluble dye; alcohol-soluble dye soluble in alcohol. Water-soluble dyes include: anionic acid dyes, direct dyes, dye leather special dye; amphoteric metal complex dyes, triphenylmethane dyes of sulfite; cationic alkaline dyes.