College of Construction Engineering��Jilin University��Changchun 130026��China

Principal Component Analysis ( PCA) can simplify the structure of database by replacing multidimensional parameters with relatively less comprehensive variables in order to ensure the minimum lost in initial data�� In this paper��eighteen black soil samples from different sites were tested and thirteen distinctive indexes were chosen to evaluate the degeneration of black soil�� By using principal component analysis��variables of thirteen dimensions can be diminished to six unrelated principal indexes�� Analysis shows that the soluble salt content��Fulvic acids ( FA) and aggregation degree have a high weighing coefficient��indicating these three indexes are the major parts for the evaluation of black soil degradation�� It also provides a new path to the degenerated black soil treatment in Northeast China��