In order to find out the crack propagation law in hydraulic fracturing conditions and crack distribution features forThree Softcoal seam,this paper combines the hydraulic fracturing test of coal seam gas field in Jiaozuo Henan based on the assumption of crack width in PKN model and frictional pressure drop law of fracture flowing.This paper focuses on fluid loss factors of fracturing fluid,finally the crack propagation and permeability calculation model of cataclastic coal under hydraulic fracturing was est...