The 3D conceptual models and relevant algorithms based on Open GL are developed for characterizing and visualizing the fracture networks and seepage paths in fractured rocks. The standard database interface and the application program interface were designed by using Visual Basic software development tool in the Windows operating platform. The OpenGL-based visualization capability was incorporated for the 3-D fracture networks and seepage paths. The model and algorithms have been tested using a large number of fracture data that were obtained from the field fracture investigation. It has been shown that the visual effects offered by the program could present a lot of fracture information and make a comprehensive understanding on the structures of the fracture network to the users. It is observed that the program developed could quickly, correctly and effectively fulfill a series of the complex and tedious displaying and processing procedures as to a 3-D fracture network. Consequently, visualization efficiency can be then significantly increased. As a result, complex processing and visualization pertinent to the fractured rocks such as groundwater flow and solute transport become more practicable at a large field scale particularly.