For the heterogeneity and random distribution in potato internal structure, the water transport process during drying was simulated by using fractal characteristics. The result showed that the model combined with shrinkage and fractal was more close to the experimental data than no shrinkage and continuum model, and the internal pressure distribution did not fall step by step in proportion as continuous model. The fractal model including shrinkage increased with pore connectivity, porosity, area fractal dimension and the ratio of the minimum and maximum pore diameters, whereas it decreased with tortuosity fractal dimension and pore tortuosity.