Abstract: Based on the engineering background of the dislocation area of surface surrounding rock in the mining goaf of a subway mine，a set of real-time monitoring and intelligent early warning technology scheme of surface subsidence in goaf based on GNSS unattended is proposed，which realizes real-time monitoring，continuous data acquisition，online identification，intelligent analysis and disaster early warning of goaf surface. Combined with the research results of surface stability of large area goaf，referring to relevant specifications，the safety warning value of the settlement monitoring system is set by engineering analogy method : surface settlement≤0.1 m/month，surface inclination≤2 mm/m，curvature≤0.2 mm/m²，settlement acceleration≤12 mm/d². The application shows that the judgment results of the intelligent monitoring and early warning system for surface subsidence are basically consistent with the actual situation on site.

Key words: surface subsidence, intelligent monitoring, safety warning