Fluorescent whitening agent DMS is considered to be a very good fluorescent whitening agent for detergents. Due to the introduction of morpholine group, many properties of the brightener have been improved. For example, the acid resistance is increased and the perborate resistance is also very good, which is suitable for the whitening of cellulose fiber, polyamide fiber and fabric. The ionization property of DMS is anionic, and the tone is cyan and with better chlorine bleaching resistance than VBL and #31.