A method for treatment of dye wastewater by using ultraviolet-acetylacetone oxidation process is provided. This method belongs to the field of dye wastewater treatment, comprising the following steps: A) adding acetylacetone into dye-containing water, stirring and mixing them completely; B) putting the liquid obtained in step A) under ultraviolet irradiation till it is effectively decolorized. Provided is a new method for decolorizing high-concentrated dye wastewater on the basis of ultraviolet-induced oxidation process of phydroxyl radicals. This method can realize complete decolorization of the dye wastewater. During the oxidation process, the dye in the wastewater acts as the photosensitizer and can accelerate the decolorization process as the reaction progresses. The method can also improve BOD5/COD ratio from lower than 0.1 to higher than 0.3, which means that this method can be used not only for high-efficient decolorization of dye wastewater, but also as a preliminary step of microorganism treatment.