With the development of the city,together with the porgress of the industry,invironment,espedially the water,is being under suriously polluted.So this design is main to do a research on every kind of urban sewage processing craft,compared with these crafts by technology and economy,and try to find a suitdble sewage process for the Hulan town in Harbin, and do a design of sewage treatment plan for the city. The total design water volume is 100000m3/d,the main body craft is A2/O craft.The A2/O craft has a simple flow, a stable movement and a nice sludge settling property ,as long as a good denitrogenation eliminates the phosphorus effect,it’s really suitable for big scale Sewage treatment plant.This design is mostly to do a calculation for various constructions of the waterway and sludgeway,and select equipments,then integrate blueprints.