Based on the fractal theory, pore characteristics of soils are discussed. It is found that the structure of soil pore is a fractal(multifractal). Diameter about 0.1 μm can be considered as the scale dividing into innerparticle and interparticle pores. The pore larger than 0.1 μm in diameter is the factor, influencing the soil deformation and its fractal dimension changes from 2 to 3.