The invention discloses a visible-
light response high energy efficiency photocatalyst prepared by composite 
activated carbon fiber (ACF) and an application method, which use tetrabutyl 
titanate as presoma of 
titanium dioxide, use absolute ethyl 
alcohol as solvents, use glacial 
acetic acid as 
hydrolysis inhibitor, and use 
activated carbon fiber as a carrier. Firstly, ions of S and Sm are used for dopping TiO2 and are loaded on the ACF carrier large in specific surface area to obtain a novel composite photochemical catalyst, therefore, a new development trend is pointed for 
industrial waste water treatment. The preparation method is simple, production can be performed at normal temperature, and industrialization can be achieved conveniently. The photocatalyst is high in catalytic activity, and low-concentration organic 
pollution in water can be reduced in a short time. Simultaneously, high-concentration and deep-dye 
wastewater can be degraded in a short time. The problem that suspending catalyst is apt to reunite and can cause secondary 
pollution and the like is solved, and the catalyst is easy to recover. Ratio of repetitive cycle utilization is high, high 
photocatalysis effect can be maintained after multiple repetitive cycle utilization, and economic cost can be saved. Activity of visible light is high, and 
under stimulation of visible light, low-concentration organic 
pollution can be decomposed fast, and high-concentration organic pollution can be decomposed fast. A foundation is laid for actual industrial application of the photocatalyst.