Anionic surfactants are the products with the longest development history, the largest output and the largest variety of surfactants. Anionic surfactants are divided into sulfonates and sulfate esters according to the structure of their hydrophilic groups, which are currently the main categories of anionic surfactants. The various functions of surfactants are mainly manifested in changing the properties of the liquid surface, liquid-liquid interface and liquid-solid interface, of which the surface (interface) of the liquid is the most important.