The fractured rock mass is complex in structure and variable in morphological parameters. Due to lack of effective techniques for direct observation of internal water flow in fractures, accurate calculation of three-dimensional permeability parameters of rock mass still remains a scientific problem. The single fracture seepage is related to the crevice fluctuation and the opening degree. The seepage in the spatial fracture network is related to the fracture communication. Based on the actual measurement of fracture morphology, this study proposes a multi-fractal model for analyzing seepage parameters of fractured rock mass. Firstly, the single-fracture wall is scanned by a three-dimensional laser to obtain the fractal dimension of the closed or open fracture surface morphology. Combined with the cubic law and Darcy's law, the single-fracture water flow is analyzed, the fractal dimension of the water flow path is calculated, and the fractal relationship between the single fracture morphology and the permeability coefficient is obtained. Then the three-dimensional fracture communication network is established by Monte Carlo method, and the two-dimensional fracture communication network in different directions is obtained through orthogonal slice. The fracture communication is described by the fractal dimension of the fracture density, and the fractal dimension of the two-dimensional and three-dimensional fracture network communication rate is established. Finally, the two-dimensional fracture seepage path and permeability coefficient are analyzed according to the undirected graph adjacency matrix and continuity equation of seepage, and the three-dimensional seepage flow coefficient of the fractured rock mass is solved by the fractal dimension of the two-dimensional and three-dimensional connectivity. The model realizes the analysis of the permeability parameters of the fractured rock mass by the fractal dimension of the fracture and the seepage analysis of complex fracture networks is conducted by step-by-step dimensionality reduction from three dimension to one dimension, which provides a new idea for the study of fractured rock mass hydraulics.