The rock mass fracture is very developed because of its special rock property in karst area

which results in the developed fracture network of rock mass

the fracture channels are very easy to form the connected network. Under the action of chemical corrosive water

the channel of fissures will be widened

which leads the leakage increase. Based on the developed characteristics of rock mass fissures in karst area

fracture network of rock mass is plotted. The development degree of rock mass fracture is simulated by using the 3-D Monte-Carlo modeling technique. At the same time

the chart of fissure connection is also simulated; and this chart can exhibit the developed direction of dominant fracture in karst area. On basis of the joint network

all kinds of fracture and pore in karst area are divided into four levels by the scale and permeability of fracture and pore; i.e. level-1 real fracture network

level-2 random fracture network

level-3 equivalent continuum and level-4 continuum; the relation of each level fracture is established by the principle of water balance. Then the seepage of rock mass fracture in karst area is analyzed in detail by adopting the seepage models of multi-level fracture networks. The investigation results show that the seepage models of multi-level fracture networks are applied to the seepage analysis of rock mass in karst area

which can reflect correctly the seepage distribution law of fracture mass in karst area; and possesses important reference meanings for solving the prevention seepage and prevention corrosion in karst area.