Abstract: It is necessary to carry out the BIM 3D design for complex deep foundation pit as conventional 2D design can hardly meet requirement.With a specific engineering case,BIM technology was applied to build 3D model of the whole foundation pit that includes the 3D model of enclosure structure,support system and complex nodes etc.BIM collaboration and BIM visualization were used to do clash check,construction process simulation and technical interpretation of design intention,which can promote communication efficiency,reasonably save resources,reduce design alteration,accurately express design intent,effectively avoid design errors and improve the construction quality.As a result,the informatization to the foundation pit is realized and the safe,effective and high-quality design and construction quality of foundation pit is guaranteed.The practice shows that BIM technology is advanced,superior and necessary in the complex deep foundation pit engineering.