Based on the analysis of eroded red soil deterioration processes, research on evaluation index sys-tem of red soil deterioration is carried out. Influenced mainly by time and biological factors, soil fertility has been restored gradually with the reclamation of eroded soil. The process of soil restoration can be promoted with much longer time and forest plantation. Correlation and factorial analyses are used to reduce the iterated information and simplify soil indexes. Six indexes are selected to indicate more than 90 percent information of all 16 soil indexes, and thus soil fertility status can be expressed by fewer indexes.