As an additive for Nd-Fe-B permanent magnets, the coercivity of Nd-Fe-B permanent magnets can be improved by adding about 2-3% dysprosium. In the past, the demand for dysprosium was not large, but with the increase of demand for Nd-Fe-B magnets, it became a necessary additive element and its grade must be 95-99. About 9%, demand is also increasing rapidly. Dysprosium is used as phosphor activator. Dysprosium trivalent is a promising active ion of tri-basic color phosphor with single luminescent center. It consists of two emission bands, one is yellow emission, the other is blue emission. Dysprosium-doped phosphor can be used as tri-basic phosphor.