Aiming at the problems of high fire hazard and low levels of intelligent fire monitoring in the historic buildings of Ming and Qing Dynasties， this article takes xBIM as the secondary development platform， establishes a database using SQL Server， and builds an intelligent fire monitoring platform， so as to realize the integrated management of the monitoring system of the huge ancient buildings. For the real-time data generated by the detector， the iterative optimization of the Mann-Kendall trend algorithm not only effectively avoids the drift problem caused by the traditional fixed threshold algorithm， but also improves the accuracy of the fire detectors. Combining the fire dynamics simulation and taking the fire hazard source and the building structure as the influencing factors， the layout of the fire detector is reasonably optimized to improve the efficiency of its detection. This article provides a set of scientific and efficient integrated management technology for the fire supervision of historic buildings in the Ming and Qing Dynasties.