Abstract: In order to solove the problem of strong pressure behavior of mining roadway in sub-level caving mining of extremely thick coal seam under goaf, taking 30501 working face in 3-5^# coal seam of SDIC Tashan Coal Mine as engineering background, varied of field measurement methods were used under the guidance of mining science and theory of the mine pressure, the stress distribution of coal pillar, the working load of bolts, the cracks and the loose circle development of roadway and the roadway deformation laws were deeply monitored and analyzed. The measurement and analysis result has fully revealed the inducement mechanism of strong pressure behavior of different positions in mining roadway in sub-level caving mining of extremely thick coal seam under goaf.