Traditional design methods are difficult to meet the complex environment of underground space, so BIM technology is applied in engineering design and construction. This paper takes Tiantian Square, a typical underground space project, as an example to discuss the application of BIM technology in the 3D design and performance analysis of the project in detail. The analysis results verify the rationality of the design scheme and provide basis for scheme optimization and pipeline arrangement. Relevant research results also serve as important reference for similar projects.