Abstract: Photocatalyst has a spacious application prospect because it can be used to turn light energy into chemical energy,manufacture hydrogen by decomposing water and reduce or oxidize pollutant into innoxious substance.But it has not been applied far and wide for it is unable to utilize sun light efficiently.Therefore,the research on the visible lighted of photocatalyst has been one of the most important issues.The functional scheme,the present state and the research results in the filed of photocatalyst are introduced systematically in this paper.