This study explores the application methods of Dynamo visual programming in bridge and tunnel engineering. It demonstrates how Dynamo facilitates engineers in the parametric modeling of bridge and tunnel structures, rebar generation, analysis, optimization, and the extraction and management of bridge and tunnel data. The paper begins by discussing the significance and complexity of bridge and tunnel engineering, as well as the applications and challenges of BIM technology in this domain. It then elaborates on the features and advantages of Dynamo visual programming. Finally, the study uses typical bridge and tunnel design issues, such as beam bridges and shield tunnels, to illustrate how Dynamo can automate the creation, modification, and analysis of Revit models, and how it can be used to extract and manage bridge and tunnel data effectively.