Urban sewage systems in China have been developing rapidly in recent years, with problems of system hydraulic failure in peak period, challenge from change of drainage scenario caused by population change, climate change, and water saving behavior; and urban form is closely related to the operation of urban facilities. This study set up urban morphology scenarios and drainage scenarios, built a top-down virtual model of urban space and sewage system, used Kruscal algorithm for network routing and SWMM software for system simulation, and sampled a large number of sewage system solutions, to explore life cycle cost, structure, and operation of urban sewage systems, and assess urban sewage systems with regard to economic performance, effectiveness, and adaptability. The study found that life cycle cost is about 600-700 million yuan for the city. The velocity failure rate of square, rectangular, and star-shaped cities is 0.55, 0.67, and 0.55 respectively, and the capacity failure rate is 0.35, 0.42, and 0.36. Under the low discharge sewage scenario, velocity failure of the system turns more serious, and capacity failure of the system is improved. Under the high discharge sewage scenario, velocity failure is improved, but capacity failure is more serious. More dispersed sewage systems have better connectedness and the sewage system of rectangular city is more centralized than the square and star-shaped cities. Correlation analysis showed that the more dispersed sewage system is more economical and effective, but the adaptability is worse. Finally, from the perspective of system economy and effectiveness, square and star-shaped cities perform better. With regard to the adaptability of sewage system, rectangular city is superior to square and star-shaped cities. Based on the urban forms of the 86 Chinese urban areas examined in this study, the development trend is unreasonable. It is hoped that the conclusion can provide some reference for future urban planning and urban form management.