Abstract: The roughness of rock fracture has an important influence on its seepage characteristics. On the basis of Barton ten standard contour line, this article adopts the numerical simulation software COMSOL to establish a coarse single fracture seepage model, and studies seepage characteristics of different rough fracture, monitoring the change of seepage velocity in the process of seepage, and the permeability is calculated by the modification of the cubic law, at the same time, the stress variation in the fracture passage is observed. The results show that:the fracture roughness has a great influence on seepage velocity, with the increase of roughness coefficient (JRC), the maximum and average flow velocity in fracture seepage decrease gradually; in the process of fracture seepage, the eddy current field is generated, and with the increase of roughness, the eddy current field becomes more and more disordered in the process of fracture seepage, and the eddy current field will affect the change of velocity field; the permeability of rock fracture increases with the increase of JRC values and shows a logarithmic increasing trend; the maximum pressure in the fracture passage fluctuates greatly under the influence of fracture roughness, when the JRC value is from 8 to 10, the maximum pressure reaches the minimum value; the minimum pressure in the fissure passage decreases with the increase of JRC value.