Abstract: Combined with the floor conditions of 1026 island coal face in a Coal Mine, the airway floor at island coal face by using Rayleigh wave detector is detected. The measuring line was arranged along 1026 coal face airflow roadway; 12 measuring points was even distributed by 1 point every 5 m starting from 5 m ahead of the coal wall along the line which is 60 m long; the detection direction was vertically downward the floor. Depth profile process showed that the most damage depth of the roadway floor was 26.3 m within the range of lead abutment pressure; the thickness of block in part of section of the island coal face was only 30 m; compared with the most damage depth of the roadway floor, the possibility of water inrush increased greatly in the range of lead abutment pressure.