ZnO is a kind of photocatalytic materials with a broad application prospect, but problems such as high carrier recombination rate limit its further application. Mn doped ZnO powders were prepared by hydrothermal synthesis. The phase composition, pore structure, luminescence property and photocatalytic properties were studied. Results show that when Mn is instead of 0.5% Zn in ZnO, Mn occupies the place of Zn in ZnO lattice. The powders have small particle size and large specific surface area. The carrier recombination is inhibited, the band gap is reduced, and the light response range is broadened. Under the condition of 8 W, 365 nm UV light, the degradation rate and COD removal of Mn0.05Zn0.95O powders over Congo red reach 97.4% and 76.34%, repectively, after 70 min irradiation. Mn0.05Zn0.95O has the best adsorption for rhodamine B, and the best degradation for methylene blue. The degradation rate over Congo red reduces by 6.6% after 4 successive cycles. The results provide technologic support for photocatalytic degradation of organic waste water.