Abstract: The article discusses the concepts, connotations and determining method of geochemical background and geochemical baseline. With the development of geochemistry, great changes have taken place in the concept and connotation of geochemical background. In the early days, attention was paid to the "quantity" of the geochemical background, while at present the "nature" is the focal point. The method of determining geochemical background values varies with different research purposes. The common point of geochemical background and geochemical baseline lies in their special reference function. It is this reference function that makes the research on geochemical background and geochemical baseline have great theoretical and practical value in environmental quality evaluation and environmental legislation.