The invention discloses a method for degrading humus organic pollutants in water by catalytic ozonation, and belongs to the technical field of treatment of environmental wastes. The method comprises the steps of preparation of a cobalt-manganese composite oxide catalyst, sewage treatment with catalytic ozonation and the like. The catalyst is easy to prepare; the method is easy to operate, rich in sources of cobalt nitrate and potassium permanganate serving as raw materials and low in price; the catalyst can be reused, and is low in treatment cost; the method has high adaptability to the water of percolate of different domestic garbage landfills; and compared with a single ozonation method, the method has the advantage that the chemical oxygen demand (COD) removal rate of the organic pollutants in sewage can be improved by about 20 percent. The method can be popularized and applied in sewage treatment of removing the humus organic pollutants from the garbage percolate and the like in each place.