The traditional project management mode of existing building transformation is always subjected to the restriction of technical means, resulting in low efficiency and difficult coordination.The introduction of BIM technology breaks the limitations of the traditional project management model, opening up new ways of thinking for managers. Taking the Shikumen building named Jianyeli in Shanghai as a case study, the BIM technology is applied in the existing building reconstruction management, integrating the 3D scanning, reverse modelling, and VR/AR technologies. Based on a collaborative platform, the basic and extended application of BIM are studied. Through practice in project, the unique advantages of BIM and "BIM+" technologies are verified. The integrated applications of these new technologies fits the development trend of more informatized and refined management, and will lay good foundations for the construction of smart cities.