Abstract: The granularity characteristics of loess, laterite and expansive soil in China are studied according to the fractal geometry. It is found that there is a linear relationship between the accumulative granularity content and the grain size in log-log plot, and it’s slope b can be used to calculate the relative fractal dimension D by the equation D = 3 - b. Results show that the D of regional soils changes from 2 to 3, and the D of laterite is the largest and loess is the lowest. Further, the D may be taken as the series-parameter, which describes the soil system as a self-organization one. The higher the value of D, the greater the degree of the self-organization, correspondingly, the evolution of the soil is in the higher stage. Correlations between fractal dimension and sorting or grading, pore-size distribution, microstruc-ture characteristics are discussed respectively. It is concluded that the fractal dimension is a better index for the description of granularity characteristics and the classification of cohesive soils.