Abstract：The technique of hydraulic fracturing has been widely applied to improve the gas permeability of the coal reservoir in many coal mines.However, the executive effects on the conditions of different destructive types and confining pressure of a coal seam are significantly different in some different coal regions.In order to make the compatible conditions clear and to optimize its applying technics and to improve the gas drainage ratio of a coal seam, some analysis has been conducted to the data in situ experiments and the practices of the hydraulic fracturing on the different coal mining regions in Henan province, some conclusions have been obtained.This technique can just be used very well to improve the gas permeability of the type I and II destructive coal seam significantly.Whereas the technique is not effective to be used for the type Ⅲ, Ⅳand Ⅴcoal seam, because only a bit small area of fractures can be extended by the hydraulic impact, while the created fractures can only be kept for a very short time in the coal seam.These conclusions are very valuable to achieve an ideal choice to the coal reservoir and to optimize the applying effects of the hydraulic fracturing technique to a soft coal seam.

Keyword：hydraulic fracturing;coal reservoir;gas drainage;technique of pressure relief and permeability improvement;adaptability;