Abstract: In order to study the seepage law of fractured rock mass, the fracture network in rock mass is simplified as a single fracture. According to the ten JRC standard profile curves proposed by Barton, a single crack cement specimen with a roughness of 10 order (JRC=1 to 20) was prepared by 3D printing technology, and the single fracture seepage test was conducted on it. The seepage law of single fractured rock mass with different roughness under different confining pressure and water pressure was studied. The results show that when the water pressure and confining pressure are constant in the seepage process of single fractured rock mass, the larger the roughness is, the smaller the permeability is; when the water pressure and roughness are constant, the larger the confining pressure is, the smaller the permeability is. however, when the confining pressure increases to 4 MPa, the decrease rate of permeability tends to be gentle; in the case of the same confining pressure and roughness, the permeability of single fractured rock mass increases with the increase of water pressure, and its law is linearly correlated.