Abstract: Due to the complex function of large commercial complex, the problem of electromechanical and structural coordination is caused. This paper takes the application of BIM technology in large commercial complex as the research object. The four core engineering scenarios of net height optimization of commercial underground garage, compression of electromechanical space in public corridor, limited arrangement of cross-layer atrium pipelines and coordinated adjustment of shops and logistics corridors have attracted attention. This study systematically analyzes the core contradictions and solutions in each scenario. The three-dimensional modeling, multi-disciplinary collaboration, net height analysis and routing optimization of BIM technology are adopted. Targeted solutions are proposed by establishing a full professional integration model, carrying out collision detection, formulating pipeline priorities, and planning maintenance channel areas. The research results show that in the office tower and commercial basement scene, the net high compliance rate is achieved. In the public corridor scene, reduce the pipeline rework rate. In the cross-layer atrium scene, the structure and electromechanical space utilization are optimized. In the shop and logistics corridor scene, it can meet the net height requirements of catering shops and the maintenance function of logistics corridor at the same time. The conclusion shows that BIM technology can effectively solve the core contradiction between 'functional requirements and spatial constraints' of large commercial complexes. The system solutions of the four typical scenarios proposed in this paper provide a replicable practical path for spatial optimization and professional collaboration of similar projects, which has important engineering reference value.