The micro-structure parameters of the actual porous media through mercury intrusion experiment were obtained, and the fractal dimension of pore distribution was calculated, taking frozen-dried potato for example. The result showed that the pores in the freeze-dried potato presented the remarkably fractal properties. A two-dimensional fractal pore network model of porous media was constructed based on the theories of homothetic reduction, fractal geometry, Voronoi diagram, along with the structural parameter of potato. Since pore microstructure characteristic was considered into the model, the parameter of network model can well reflect the microstructure of porous materials, and the reasonable fractal dimension was obtained.