Abstract: Through study on the overburden rock fracture caused by mining，the paper explores the factors for surface subsidence and its temporal and spatial relations between the overburden rock fracture and surface subsidence. From the angle of micro seismic phenomenon induced by rock fracture，with the micro seismic orientation principle，the micro seismic calculation model is established. With the microwave only，and without considering the amplitude，frequency and energy，as long as each detector is able to detect the maximum moment with the same nature，the spatial orientation for the rock fracture（micro-seismic source）can be realized. Thereby，the instant position of rock fracture can be determined according to the maximum value moment. And then，the micro-seismic wave velocity is fixed to study the internal causes of surface subsidence.

Key words: Rock masses fracturing, Micro seismic, Luminance function, Travel time relation