The close distance between working face and water burst position brings hidden danger to normal production, floor damage depth information in mining area is needed before mining. Based on this problem, strain method was adopted to monitor floor damage depth information, the monitor project was located in working face roadway with similar geological condition, the new mining inclines to the drilling hole of the working face, strain sensor was set in drilling hole, floor damage depth was settled based on limit strain variables, the largest damage depth of mining floor was set by analyzing observation result, it was concluded that 10112 working face was without water burst danger. The practice showed that the evaluation was right, provided data analysis basis for working face floor water burst evaluation before mining and important basis and technical support and parameters for measures of water prevention and control.