It is difficult to implement BIM technology in project cost management due to the importance of project engineering calculation information in construction projects and the dependence of computer hardware in traditional BIM software. In this paper, the deduction relationship among concrete member column, beam, and slab is revised by Dynamo. The revised model is lightened by using Revit secondary development, then exporting glTF light format, structural tree file controlling the aggregation relationship of members, and the list quantity of work in accordance with China's pricing specification. Finally, based on Three.js graphics engine, the BIM lightweight platform is built by HTML, CSS and JavaScript to achieve the fast loading of BIM models on the website. By using component UniqueID, the paper succeeds in the matching model components with list quantity information and achieves online statistics of quantity information on the web platform. Finally, the BIM model case is imported to verify that the actual effect of this study meets the requirements.