Analyzing and comparing the concentration of bicarbonate in groundwater and surface water, the author of this paper presumed that the release of deep CO₂ causes the dead carbon in the carbon stock to be mixed into underground water, suggesting that the ¹⁴C dating method is not suitable for groundwater dating in the Subei Basin. The cycle of groundwater determined by tritium analysis is about 40a, and the hydrogen and oxygen isotopes also do not support the hypothesis that the groundwater originates from lateral recharge of groundwater from the Yangtze River. Combined with the evidence of hydrogeology, it is concluded that confined groundwater in the Subei Basin is probably recharged by deep circulation groundwater and the concealed craters and faults may act as the paths for groundwater discharge.