针对基坑施工环境复杂多变、存在不确定性等问题，容易引起基坑坍塌、滑落等危险，给人民的生命财产安全造成威胁。以广州南沙220千伏口岸开关站工程为研究区域，利用倾斜摄影测量建立真实场景的GIS模型，利用标准设计建立BIM模型，通过数据格式转化方法实现BIM和GIS的集成，实现工程量偏差可视化预警、安全风险可视化评估。提出一种基于灰色关联分析的最不可靠点判定方法，实现监测点的筛选。通过对8个形变监测点的灰色关联分析，由实验可得：最可靠点是WY04，关联度是0.852；最不可靠点是WY07，关联度是0.621，实现了监测点的筛选和可靠性的判断。研究表明，BIM和GIS的集成及灰色关联分析法为基坑安全监测提供新的参考。

In response to the complex and uncertain construction environment of foundation pits, it is easy to cause hazards such as collapse and sliding, posing a threat to people's lives and property safety. Taking Guangzhou Nansha 220 kV port switching station project as the research area, we used oblique photogrammetry to establish a GIS model of real scene, used standard design to establish a BIM model, and integrated BIM and GIS through data format conversion methods to achieve visual warning of engineering quantity deviation and visual assessment of safety risks. We proposed a determining method for the least reliable point based on gray correlation analysis to realize the monitoring points screening. The grey correlation analysis results of 8 deformation monitoring points show that the most reliable point is WY04, with a correlation degree of 0.852. The least reliable point is WY07, with a correlation degree of 0.621, which enables the screening of monitoring points and the determination of reliability. The integration of BIM and GIS, as well as the grey correlation analysis method, can provide new references for foundation pit safety monitoring.