Abstract: Hard top coal caving is difficult in 2303 fully mechanized top coal caving working face in the second horizontal and third panel area of Cuijiagou coal mine, Shaanxi province, resulting in poor caving effect, low drawing height and recovery rate.In order to solve this problem, according to the hydraulic fracturing control technology principle of hard top coal, a hydraulic fracturing borehole with a diameter of 32 mm was constructed between the supports of fully mechanized caving working face in front of the coal wall to conduct the hydraulic fracturing test of hard top coal.After the test for a period of time, the top coal was successfully weaken; the caving performance was improved; the possibility of arch structure of the top coal in fully mechanized caving face was reduced due to insufficient caving; the drawing height and recovery rate of the working face were improved; the dust concentration in the working face was effectively reduced and the working environment of workers was improved.It has important reference value to deal with the collapse of hard top coal.