Abstract：Take for example the geochemistry of Changtai, Zhangzhou and Longhai in the downstream area of the Jiulong River, Fujian, by using the data of multi-target regional geochemical investigation, this paper discusses the method of geochemical classification of soils and proposes a scheme of classification and nomenclature and diagnostic criteria. The soils in the area is divided into four major classes: Fe-Al soil, Si-Al soil, Al-Si soil and siliceous soil, of which Si-Al soil is further divided into four subclasses: ordinary Si-Al soil, ferruginous Si-Al soil, potassic Si-Al soil and pyritic Si-Al soil. The average contents of 52 elements of various soils (siliceous soil excluded) and their uses in agriculture are investigated.