Abstract: Small structure is the main cause that makes coal resource recovery difficul and induces coal mine safety accident. ISS (In-Seam Seismic) exploration technology was used to detect the working face 11061 in Yi'an coal mine.Small structure whose dimension is as the same as the coal seam thickness and are of high rock stress as well as mine gas abundante zone in working face could be discovered using ISS CT technology. The result can serve as reference for safe recovery of coal resource in coal mines.