Abstract: With the rapid development of urban rail transit in China, the construction of inter-station tunnels has become a critical component of urban rail transit engineering. Addressing the current issues of low efficiency and significant difficulty in BIM modeling for open-cut tunnel construction, this study has researched and proposed a parametric modeling method for open-cut tunnels. A corresponding modeling program has been developed based on the Revit software platform. Initially, the study summarizes the cross-sectional characteristics of open-cut tunnels and designs an information model for open-cut tunnels, including design and layout information of tunnel cross-sections and the integration with route element information. Subsequently, a program for calculating the route mile points has been designed and implemented, which can accurately calculate the spatial coordinates of any mile point based on the route curve elements, meeting the precision requirements for information model construction. Finally, an automatic modeling plug-in for open-cut tunnel models has been developed based on Revit, where users only need to input parameters such as tunnel cross-section and layout position to automatically generate a three-dimensional model of the tunnel. The practicality and accuracy of the plug-in have been verified through the case study of the Yuzhu return line project on Guangzhou Metro Line 13. The plug-in not only improves the efficiency of BIM modeling for open-cut tunnels and reduces the difficulty of model establishment but also promotes the application of BIM technology in tunnel engineering. It holds reference significance for parametric design and information-based construction.