The invention discloses Ni-doped Cd0.1Zn0.9 S microsphere photocatalyst and the preparation method thereof, the particle shape of the produced photocatalyst is a microsphere formed by nanometer crystals, and the doping amount of Ni is 0.1 percent to 0.5 percent of the weight of the catalyst. The invention has the preparation method that zinc sulfate, cadmium sulfate, nickel nitrate, and thioacetamide are taken as raw materials to form mixed solution which is sealed in a hydrothermal caldron and then laid in a baking oven to be insulated, naturally cooled to the room temperature, a resultant is obtained through cleaning, drying, and grinding. The Ni-doped Cd0.1Zn0.9S microsphere photocatalyst is prepared by the invention, and the anti-surface oxidation capability in air and the photo-corrosion resistant capability in the photocatalytic reaction are evenly enhanced greatly. Because the particle of the photocatalyst is microsphere-shaped, the photocatalytic activity for photocatalytic water splitting into hydrogen of visible light of the catalyst is greatly enhanced, and the highest hydrogen production rate reaches 191.01 micromole / (g*h). The quantum efficiency reaches 6.77 percent at the 420 nm position. After Pt of 0.6 wt percent is loaded, the highest hydrogen production rate reaches 585.45 micromole / (g*h), which is three times than the hydrogen production rate when the Pt is not loaded. The quantum efficiency reaches 15.9 percent at the 420 nm position, the activity is high, and the stability is good.