Abstract: Large and complex projects are increasingly adopting information technology such as BIM to improve project collaboration efficiency, but some of them have not achieved the expected results. Through engineering practice, it has been found that the failure lies in the misunderstanding of information collaboration theory, the unclear goals, the undefined implementation steps, and overlooking the systematic work related to the promotion process of information technology work. This article explores the construction process of an information collaboration platform for large and complex projects. By reviewing the theories of large-scale and complex project management and information collaboration, calculating collaborative data flow, and summarizing the difficulties in information transmission, the article proposes the requirements and necessity of information collaboration for large-scale and complex projects and the function and construction scheme of the information collaboration platform based on BIM. Taking Chongqing Jiangbei International Airport as an example, this article introduces the construction of the platform and the results achieved.