Dyes are substances that can make fiber fabrics or other substances dye bright and firm colors. According to the properties and application methods of dyes, dyes can be divided into disperse dyes, reactive dyes, sulfide dyes, vat dyes, acid dyes, direct dyes and so on. Dyes and dye intermediates are not only China's traditional advantageous industries, but also important industries related to the basic people's livelihood. Since the global production focus shifted from Europe and the United States to China at the end of last century, China has become the world's largest dye country.