Abstract: Macrofractrues were classified into four ranks,according to measurement and statistics of underground coal mine in central and southern Xinshui basin,and the description and measurement of microfractures under scan electron microscope.Based on the analyses of relationships among permeability and ground stress/buried depth,fractures,reservoir press,hydrogeological condition,it is pointed out that the ground stress/buried depth is the principal control factor.When the buried depth is similar,the other factors play more important role on permeability.