Abstract: The key of gas control is to solve the problem of low permeability of coal seam, and hydraulic fracturing technology is an effective way to solve the problem. Based on the research results of domestic and foreign scholars on hydraulic fracturing, this paper combs the research status of underground coal seam hydraulic fracturing theory, process technology and fracturing equipment, analyzes the research progress of fracture propagation law and model of hydraulic fracturing theory, as well as the more advanced directional hydraulic fracturing technology, pulsating hydraulic fracturing and fracture network fracturing technology. The development direction of hydraulic fracturing technology in coal seam is pointed out:the basic theory of hydraulic fracturing need to study by many means; diversified hydraulic fracturing technology suitable for all kinds of coal seams need to develop; the integration and intellectualization of hydraulic fracturing equipment need to achieve. It has a certain reference significance for the development of hydraulic fracturing technology.