The fractal theory,as a new study tool, is popular in recent years. Analysis indicated the fractal dimensions of soil particle distribution could objectively reflect the structure state and degradation degree of the degraded soil,so they can be used as a comprehensive quantitive index to evaluate the structure of the degraded soil. There are the significance and correlation between fractal dimensions of the degraded soil and the mechanical composition and microaggregate composition of the soil. Higher the content of <0.001 mm clay and lower that of >0.25 mm microaggregate,higher the fractal dimensions and worse the structure property of soil. To the same soil degradation series, higher the fractal dimension, more serious the soil degradation.