<p>The difficult caving of the hard roof during the horizontal slicing fully mechanized top coal caving mining in steep thick coal seams can easily lead to major safety accidents such as gas explosion. To ensure timely and sufficient caving of the roof, this article puts forward the hydraulic fracturing control method of the hard roof during horizontal slicing fully mechanized top coal caving mining in the steep thick coal seam on the basis of analyzing the disaster mechanism of gas explosion accidents caused by hard roof. The pulse hydraulic fracturing technology is used to weaken the roof and top coal, while the directional hydraulic fracturing technology is used to cut off the connection between the roof directly above the goaf and the lower strata, so as to accelerate the roof cave. Compared with before hydraulic fracturing, after hydraulic fracturing, the volume of the goaf cavity can be reduced by about 91%. In addition, the parameters of the roof caving area are also provided. This method has been successfully applied in coal mine site. After the hydraulic fracturing area enters the goaf, the goaf roof caved behind the tail beam of the hydraulic support, and the caving gangue basically fills the goaf.</p>