The invention discloses a sulfur-indium-zinc, gold and carbon nitride two-dimensional lamellar composite photocatalyst preparation method. The method includes: dissolving C6H5Na3O7 2H2O into dissolvedwater, diluting HAuCl4, heating to boil, adding sodium citrate solution, boiling, and cooling to the room temperature to obtain gold colloid mixed solution; dissolving g-C3N4 into ethyl alcohol, performing ultrasonic treatment, dissolving Zn(NO3)2 6H2O, In(NO3)3 4.5H2O and L-Cysteine into glycerin and the gold colloid mixed solution, mixing with g-C3N4 solution, and adsorbing to obtain ZnIn2S4/Au/g-C3N4 precursor solution; performing heating reaction in a hydrothermal reaction kettle, and performing vacuum freeze drying to obtain powdered sulfur-indium-zinc/gold/carbon nitride two-dimensionallamellar composite photocatalyst. By adoption of the method, easiness in raw material acquisition, one-kettle synthesis, high reliability and simplicity and convenience in operation are realized, andthe catalyst has high photocatalytic activity in a visible region and has a promising application prospect.