Abstract: The Beijing Land Subsidence Monitoring System consists of land subsidence monitoring network, leveling monitoring network, GPS monitoring network, groundwater dynamic monitoring network and InSAR monitoring network. Based on the information accumulated through the land subsidence monitoring work of Beijing City in recent years, this article analyses and summarizes the bedrock bench mark and layered bench mark monitoring and quality control method. The two-level monitoring method, i.e. GPS monitoring control network and monitoring network, improves the monitoring accuracy. The InSAR method is adopted to initiate the land subsidence special monitoring research on some important rail traffic. The article also gives some guidance for land subsidence monitoring network construction and optimization.