Because of the fluctuations of pollutant concentration and quantity of decentralized sewage, large-scale centralized treatment is difficult to achieve. So the characteristics of water quality and quantity of decentralized sewage, the stability of treatment process, the costs of maintenance and management were analyzed as the suitable technical requirement of decentralized sewage treatment. The analysis of representative treatment at present is given. No sludge in long periods, maintenance frequency and professional requirements for maintenance operation in a low level, reactor in a stable operation when large fluctuations in water quality and quantity and climate change should be included as the characteristics of the appropriate treatment process.