Abstract: In order to grasp the deformation regularity of open-pit slope in time，a set of real-time dynamic to reflect the auto-monitoring system of slope deformation was established based on the GPS (Global Positioning System) monitoring technology，network communication technology and computer technology，etc.The system adopts high precision GPS to obtain the 3D(3 Dimensions) coordinates of the monitoring points，and then uses GPRS(General Packet Radio Service) communication module to send data package to the computer.The data can be calculated into image data processing software to realize the automation of the slope deformation monitoring.Taking the North Haizhou open-pit as the object of monitoring，the monitoring results show that after a period of monitoring，the average slope horizontal displacement deformation is 52.6 mm，the average slope vertical displacement deformation is 17.3 mm，the average horizontal displacement rate was 0.33 mm/d，the average vertical displacement rate was 0.11 mm/d.The Construction of slope deformation monitoring system has achieved high precision and auto-monitoring，thus providing effective technical support for dynamic disaster warning and timely making safety decisions.

Key words: GPS, Slope stability, Auto-monitoring, Slope deformation monitoring system