This paper introduces a real-time monitoring system by using wireless sensor network (WSN). And this is a real application on inclination monitoring on the diaphragm wall of an excavation engineering project, which is adjacent to a metro line in Shanghai. According to Shanghai local regulation, the maximum lateral displacement of retaining wall should be less than 0.14%H (i.e. excavation depth). As for the monitoring of wall deformation, buried inclinometer with manual measurement is widely used. However, it is hard to obtain continual data for the timely warning by the conventional method, especially under a critical condition such as rainy or hazy days. Besides, measurement data of different monitoring points can’t be acquired simultaneously. The applied WSN system on the diaphragm wall consists of 48 tilt nodes and a gateway. A project cloud platform allows all interested parties to access the data, and it helps to recognize an early damage signal quickly and analyze the diaphragm wall in a spatial manner. The monitoring system the paper introduces might be helpful for those excavations that require real-time monitoring under severe ground conditions, or those adjacent to tunnels as in this case.