Abstract: It is important for coal pillar mining under buildings，railways and water-bodies and perfecting coal mining subsidence prediction theory to study mining-induced subsidence law of thick loess layer.Based on 6204 working face of Yangwangou Coal Mine，borehole TV detection equipment and real-time monitoring equipment for measure points subsidence value were used respectively，to detect inner mining induced fracture and reveal subsidence law of thick loess layer.It shows that thick loess layer has good integrity，and has no inner mining-induced fracture.Furthermore，it is obtained that thick loess subsidence as a whole，whose subsidence value approximately equal to surface subsidence value，and keeps in step with the surface.

Key words: Mining subsidence law, Thick loess layer, Mining-induced fracture