The invention relates to the technical field of sewage treatment, particularly method and device for combined utilization and advanced purification of waste water at different pollution levels. The method comprises the conventional sewage treatment steps of sewage collection, physicochemical treatment, anaerobic treatment, aerobic treatment and sand filtration, in addition of a sewage control step. In the sewage control step, the chemical oxygen demand (COD) of sewage is controlled by using waste water at different pollution levels. In the physicochemical treatment step, the multi-stage physicochemical treatment method is adopted, and the physicochemical pond device structures and the physicochemical agents in the individual stages are different from each other, thereby reducing the COD value and the colority of the sewage and achieving the pretreatment effect before biochemical treatment. The sewage treatment method and the sewage treatment device can reduce the COD value of sewage from ten thousand to one hundred and ensure that the sewage meets the sewage drainage standard. The sewage treatment method and the sewage treatment device have the advantages of stable quality of the treated sewage, high treatment capacity and low treatment cost.