Laser diffraction(LD)technique and pipette method were used to measure particle size distributions(PSD)of 60 ferrosol samples. Based on the measurements,mass fractal dimension,D_m,and volume fractal dimension,D_v,were calculated and compared. Results show that D_v is lower than D_m because the laser diffraction technique "underestimated" the clay fraction compared to the pipette method. As significant linear correlations were observed between D_v and D_m as well as between D_v and its measured clay fraction,D_v could also be used to characterize some basic soil properties. The LD method could divide soil particle size into more classes with distinctive D_v value. Further division of particle size classes might lead to slight decrease in D_v.