Pore structure of sandstone has much influence on its hydrophilic characteristics. The results of pressured-mercury testing for sandstone are discussed in the paper with the help of fractal geometry theory. The effect of pore structure for sandstone is mainly discussed, combined the results of hydrophilic experiment. Results show that the pore structure of sandstone has single and multiple characteristics within some pore size. Four typical fractal characteristic are defined in the paper and it is found that characteristic of pore structure has much relation with its hydrophilic characteristics: hydrophilic rate of Sandstone with A or C-type fractal microstructure changes little and the double logarithmic hydrophilic relationship curve is always linear; however, the hydrophilic rate of ones with B and C-type fractal microstructure changes greatly and always taken as concave-convex.