To study the particle size distribution, effects on erodibility and to clarify the relationship between soil particle size distribution and erodibility of six land use types in karst district, we combined field sampling and laboratory analysis of the soil particle composition, and the differences in soil particle distribution, fractal and erodibility. The six land use types included forest land, shrub land, scrub, grassland, returned farmland and cultivated land. The results showed that the mass fractions of silt, clay and sand decreased successively among the studied six type use lands. The sand mass fractions of shrub land and scrub were significantly higher than those of returned farmland and cultivated land, and the clay mass fractions of returned farmland was significantly higher than those of shrub land, scrub and grassland. The soil fractal dimension was 2.822-2.873. The soil erodibility of shrub land, scrub, grassland, woodland, cultivated land and returned farmland decreased in turn. Soil fractal dimension was significantly negatively correlated with the mass fractions of soil sand and silt, and significantly positively correlated with the mass fraction of clay. Soil erodibility was significantly positively correlated with the mass fractions of soil sand and silt, and negatively correlated with the mass fraction of soil clay. The maximum relative error between the fitting value of soil fractal dimension and the measured value was 0.11%, and the minimum was 0.03%, which showed that the model had high reliability and accuracy and could be used to calculate the fractal dimension of soil particles instead of the measured method. Shrub land and scrub soils were most vulnerable to erosion in karst mountainous areas, and their prevention and control should be strengthened, especially in areas with high slopes.