Monitoring and maintenance of sewer system is important to city water environmental management. A method for pipeline monitoring and maintenance decision support system (PMMDSS) based on geologic information system (GIS) and decision making system (DSS) is developed for upgrading sewer system maintaining efficiency. Visual basic (VB) and standardized Active X components are employed in PMMDSS, which selected SuperMap Objects as the development platform. PMMDSS integrates the spatial and model system to achieve the decision analysis for the sewer system monitoring and maintenance. An application Software is developed based on a case study in Yuechi Country of Sichuan Province. The software can be used to dynamically monitor the heath condition and provide an optimum visual decision making platform for the city sewer system.