Abstract: There are more and more dynamic disaster when the hard roof is broken, so the hyaraulic fracturing technology was used on the 1103 working face. It tested the ruslt by field observations, borehole imaging, micro-seismic monitoring, and compared with the effect of the bursting roof. It was found that the transverse fracturing radius was greater than 15 m, and the longitudinal fracturing radius was greater than 9 m when hydraulic pressure was more than 30 MPa and the time was more than 30 min, the average energy and total energy of microseismic evented dropped sharply when the work face was in the area of hydraulic fracturing, and the falling range was more than the burst area.

Key words: "Three hard", coal seam, Dynamic disaster, Hydraulic fracturing, Effect test