Taking six typical epikarst systems in China as examples, the authors summarize their features of geochemical variations, and analyze their environmental significance. It has been found that the geochemical variations in typical epikarst systems of China are characterized by the seasonal changes of CO2 content in the soil, which tend to increase yearly or monthly; and the CO2 effect and dilution effect of the HCO3- content in ground-water. The former possibly reflects the influence of global warming, while the latter shows that the epikarst system acts as a good adjuster to atmospheric CO2.