Based on the results of in-situ determination using electrochemical methods,oxidation-reduction regimes of major natural soils,upland soils and paddy soils in China were systematically summarized for the first time.The natural soils and upland soils belonged to the category of oxidizing soil,with Eh in the range of 440～730 mV,and content of reducing substances equal to 0.00～4.01×10^-5mol L^-1 of Mn²⁺,and remained basically oxidizing within a year,oxygen being the Eh-determinging factor and quite weak in transformation and translocation of materials in the soils,while the paddy soils ranged between 670～-70 mV in Eh,with the content of reducing substances equal to 0.01～17.8×10^-5mol L^-1 of Mn²⁺,and reducing substances being the Eh-determining role.And their material transformation/translocation intensity and speed was far greater than that in the natural soils and upland soils.In terms of oxidation-reduction regime varying periodically with water regime,paddy soils could be divided into three types,i.e.oxidizing,oxidizing-reducing and reducing.Soil oxidation-reduction regime is characterized by close correlation between Eh and content of reducing substances,spatial and horizontal variation,heterogeneity, wider range of variation and high reversibility.Determination in situ with electrochemical methods has paved a way to research of oxidation-reduction properties of weakly reducing soils.