Abstract: Municipal pipeline BIM design and application are involved in pipeline engineering, municipal ancillary projects, and subway pre-construction projects, etc. However, the current native BIM software has limited support for drainage pipeline design functions, and it is unable to modify the model design scheme from the network system level, and there are also shortcomings in localization, which cannot truly be used by project design personnel. Therefore, this study analyzes the main needs of municipal drainage pipeline design work, studies the deficiencies of existing native BIM software in pipeline design functions, and carries out secondary development work based on the Bentley software platform using C++ and C# languages, optimizing the software operation logic, driving model creation with design parameters, accumulating local national standard drainage manhole model components, and forming a relatively complete set of municipal drainage pipeline design software. This software includes functions such as plane design, vertical design, manhole selection, and engineering quantity statistics, meeting the main design and professional collaborative needs of municipal drainage pipelines, and greatly improving the efficiency of BIM forward design.