For ground freezing and pile-support deep foundation pit of south anchorage of Runyang Bridge, ground freezing made the mechanic state of foundation pit become complex. According structure character of ground freezing and pile-support deep foundation pit, and the engineering geological condition of site, the large safe monitoring system was built. This paper introduced engineering geological condition of site, structure of foundation pit and monitoring system. Analysis the change rule of several kinds of monitoring data, and the feedback analysis was made based on the construction monitoring, guarantee the safety and stability of ground freezing and pile-support deep foundation pit of south anchorage. The monitor result indicated the ground freezing and pile-support method is viable for deep foundation pit, and the experience was backlog for construction of similar engineering aftertime.