Abstract: An alternative method is explored to predict effective diffusion coefficient of solute in porous media by using the fractal approach. A fractal capillary tube model is established to be an improvement of the classical sinuous capillary tube model and a power law equation is derived. The power exponent is a function of pore volume fractal dimension and surface fractal dimension,which respectively characterize the hierarchical structure and the tortuosity of pores. Analytical comparison of the reported experimental data of fractal dimension of clayey soils with the corresponding effective diffusion coefficients indicates that the derived power law equation is valid to predict the effective diffusion coefficient of solute in porous media.