The present paper deals with forms of organic C, N and P and their distribution, as well as their supplying capacities of the nutrients in three black soils with different fertilities (virgin, fertile and infertile black soils).The contents of organic matter and major nutrient elements in virgin black soil are more than those in cultivated soils including both fertile and infertile black soils. The content of total C, N, P and organic P dicreases in the following sequence:virgin soil>fertile soil>infertile soil.Under reasonable cultivation, fertile soil applied with organic manure is characterized by:(1) higher content of organic C and thick cultivated layer;(2) more humic acid A and fulvic acid in subsoil than those in surface soil;(3) more humic acid B and humin N in subsoil of fertile soil than those in subsoil of virgin and infertile soils;and (4) decrease of highly stable organic P and increase of moderately active organic P. These characters mentioned above indicate the greater potential and supplying capacity of major nutrients of fertile black soil.