本文以江西省临川县不同肥力水平的红壤为对象，进行研究结果表明，随着肥力水平的提高，红壤复合体中碳氮含量也随之增大；红壤复合体中碳氮含量以１～２μｍ粒径最大，＜１μｍ，２～５μｍ粒径略有减少，５～１０μｍ粒径明显减少，１０～５０μｍ粒径成倍减少，红壤氮碳主要集中在＜１μｍ粒径的红壤复合体中。培肥土壤，提高土壤肥力可减少红壤复合体对磷的吸附，增加磷的解吸，从而增强红壤磷的有效性。 In this paper, the red soil with different fertility levels in Linchuan County, Jiangxi Province was selected as the research object. The results showed that with the increase of fertility level, the carbon and nitrogen contents of the red soil complex also increased. The diameter of 2μm to 5μm decreased slightly, the size of 5μm to 10μm decreased obviously, while the diameter of 10μm to 50μm doubly decreased. The red carbon was mainly concentrated in the red soil complex with the size of 1μm. Fertilizing the soil and increasing the soil fertility can reduce the adsorption of phosphorus by the red soil complex, increase the desorption of phosphorus, and enhance the availability of phosphorus in the red soil.