Abstract: Aiming at the potential safety hazards caused by the horizontal displacement and settlement of the building's foundation pit wall and the foundation pit slope during the construction of the building, a monitoring system for the displacement of the foundation pit wall is designed. The BeiDou Navigation Satellite System (BDS) observation data is collected regularly by measuring points and combined on the server. The reference station data sequence is used to process the displacement monitoring data of each monitoring point. Finally, the Shewhart mean value control chart is used. When the displacement of the measuring point exceeds the threshold, the system will give an alarm. The measuring point will give a set of measured values every 60 minutes, which is quasi-static. The test results show that the system can achieve a precision of 5 mm in the east (E) direction; 4 mm in the north (N) direction; and 9 mm in the up (U) direction for monitoring.