The invention relates to a method for preparing a novel CdS / MIL-53(Fe) visible-light-induced photocatalyst. The method comprises the following steps: firstly, preparing an MIL-53 (Fe) material from ferric trichloride, terephthalic acid and N,N-dimethyl formamide in a molar ratio of 1:1:65 by adopting a solvothermal method; respectively weighing cadmium acetate, thioacetamide, polyvinylpyrrolidone, ethylene glycol and MIL-53(Fe) with corresponding mass according to the mass ratio of cadmium sulfide to MIL053(Fe) being (1-1.5):1, dispersing MIL-53(Fe) in ethylene glycol, and sufficiently stirring; adding cadmium acetate, and sufficiently stirring until cadmium acetate is completely dissolved; and adding thioacetamide and polyvinylpyrrolidone, and sufficiently stirring until thioacetamide and polyvinylpyrrolidone are completely dissolved, transferring into a reactor to react for 12 hours at 180 DEG C, centrifuging, washing for 5-6 times with redistilled water and absolute ethyl alcohol, and drying for 10 hours at 60 DEG C to finally obtain the CdS / MIL-53(Fe) visible-light-induced photocatalyst. In the CdS / MIL-53(Fe) visible-light-induced photocatalyst, spherical CdS has an average grain size of 10nm and is uniformly distributed on the surface of the MIL-53(Fe) material. The visible-light-induced photocatalyst has excellent catalytic activity, and has a degradation rate for rhodamine B being 71-90 percent.