Fluorescent whitening agent is basically a kind of colorless fluorescent material. It can absorb 300NM ultra violet light and emit the visible light of more than 500NM, i.e., blue or violet light. Brightening agent can whiten the white plastics, or increase luster of the colored organic pigments. Considering the ultraviolet absorbent overlaps the ultraviolet absorption section of the fluorescent whitening agent, if whitening agent and ultraviolet absorber are used together, it can reduce or lose the whitening effect, so it is recommended that whitening agent be used only in the formula of no ultraviolet absorbent.