It is a new research direction to quantitatively reconstruct the paleoclimate and paleovegetation on Chinese Loess Plateau. Carbon isotopes of organic matter of loess/paleosol sequences have been widely used in quantitative reconstruction of paleovegetation. However, it is a new attempt to quantitatively reconstruct the paleoprecipitation by soil δ13Corg values. Because the relationships between the carbon isotopes of soil organic matter and the biomass and the climate are relatively clear, therefore, it is reliable to reconstruct the paleovegetation and paleoprecipitation from soil δ13Corg analyses. Since some problems still exist in the quantitative investigation of the past climatic changes, the following works should be paid attention to in the future: （1) the carbon isotopic fractionation during vegetation turnover to soil organic matter in the different ecosystems, and (2) the relationship between more climatic and environmental factors and the soil δ13Corg values.