By centering on the domestic and foreign research results, current situation and development trend of sewage treatment and energy saving, the experts and scholars from domestic design enterprises, colleges and universities, and research units and enterprises wrote hundreds of articles and cases about the upgrading of urban sewage treatment plants, reclaimed water reuse, equipment and instruments for sewage treatment, etc. based on the actual work, which can promote our national sewage treatment industry to develop the new technology, new process and new equipment of energy saving, and can provide some practical and valuable reference material for the choice of technical proposals and equipment.