Abstract: A concrete frame structure needs to be reconstructed due to functional updating. In order to meet the requirements of large space, massive columns, beams, and plates need to be demolished, which indicates a high safety risk. Therefore, finite element analysis was carried out to simulate structural state changes during the demolition and optimize reconstruction and monitoring schemes. During the reconstruction, automatic monitoring and manual inspection were adopted to monitor the inclination, settlement, deflection, and damage of the structure. It is shown that the measured values are in good agreement with the construction simulation and analysis results, and there is no alarm and no obvious structural damage during the monitoring period. The combination of construction simulation and monitoring can effectively reduce structural safety risks during the reconstruction.