With the advancement of urbanization,the challenges in architectural design under complex terrain conditions have been increasing.BIM technology,with its powerful 3D modeling and data analysis capabilities,provides new solu-tions for the design of complex mountainous sites.Through the study of an ecological city project,the application of BIM in various stages such as road design,retaining walls,and infrastructure is analyzed.The paper discusses the advantages of BIM in improving design accuracy,optimizing construction plans,and ensuring design implementation.The research demonstrates that BIM...