Abstract: The issue of printing and dyeing wastewater limited China’s printing industry. The recent researches were focused on photocatalysis of the semi-conductive materials like Cu2O. A serial of Cu2O were prepared by one-step reduction reaction. Then, the degradation experiments were carried out by changing the conditions like the Cu2O morphology, particle size, quantity, the reuse, etc. Last, the paper disclosed that the optimistic rate degradation of methylene orange (20 mg/L) was more than 90% during 16 hours without direct-sunlight and other extra-fixings. And the prospective catalytic concentration was 1.2 g/L, as soon as particle size, morphology was 2 μm and spherical morphology, respectively. At the same time, the matter of particles aggregation and reused were resolved by adding hydroxypropyl methylcellulose as matrix materials.