Abstract: In order to study the application of CO2 phase-transforming fracturing technology on coal seam roof weakening, the technology of fracturing on coal seam roof was analyzed and engineering experiments were conducted. The effect of fracturing was observed by the change of pressure monitoring system of fully mechanized mining support and explosion proof camera and drilling peep instrument. The results show that the effect of CO2 phase-transforming fracturing technology was significant, the distance of first step of the working face to press the step advanced for 18 meters comparing with the average distance of the mine. The safety factor increases comparing with traditional explosive technology. This technology provides references for other mines to mine safely in fully mechanized caving face.