The strategy for disposal of high-level radioactive waste in china is to enclose the spent nuclear fuel in sealed metal canisters which are embedded in bentonite clay hundreds meters down in the bed-rock. The choice of container material depends largely on the redox conditions and the aqueous environment of the repository. One of the choices for the fabrication of waste canisters is copper, because it is thermodynamically stable under the saline, anoxic conditions over the large majority of the container lifetime. However, in the early aerobic phase of the geological disposal the corrosion of copper could take place, and the corrosion behavior of copper would be influenced by the complex chemical conditions of groundwater markedly. Pitting corrosion of copper often take place in power plants or air-conditioning condensate water. The corrosion environment usually contains HCO3- SO42-and Cl-. In the early stage of geological disposal, if the aerobic water with HCO3- SO42-and Cl- immersion repository, the pitting corrosion of copper may occur. Some researchers believed that SO42-and Cl- would promote the occurrence of pitting corrosion of copper, and HCO3- will lead to surface passivation and inhibit pitting. Dong Junhua considered that in the solution with HCO3- and SO42-, HCO3-could firstly promote and then inhibit pitting. In order to study Cu pitting thermodynamic behavior in the groundwater, pitting corrosion of copper in the three-ion hybrid system has been researched in the solution with [HCO3-]=0.08mol/L and Cl-/SO42-, by the means of cyclic polarization test and SEM microscopy. The results showed that in the mixed solution of [HCO3-]=0.08mol/L ,SO42-/Cl- , SO42- and Cl- could promote the anodic dissolution of copper electrode, Cl- could reduce the corrosion potential of Cu to enhance its electrochemical activity. In the area picture of pitting sensitivity of Cu, the pitting critical concentration of Cl- was 0.02mol/L.When [Cl-] was low, pitting susceptibility of Cu was not significantly effected by SO42-; when [Cl-] was in the center, SO42- played a significant inhibitory effect on Cu pitting; when [Cl-] was high, SO42- played a reducing role in the first and then a increasing role in pitting susceptibility of Cu. Regardless of the concentration of SO42-, Cl- could promote the pitting of Cu. In this system, the self-catalytic effect of Cu pitting was sensitivity to SO42- and Cl-.