The removal characteristics of H14CO3 − ions from IRN-150 mixed resin contaminated with 14C radionuclide and the gasification effects of 14C radionuclide on 14CO2 are investigated in this study. The stripping solutions used for the removal of 14C from spent resin are NaNO3, Na3PO4, NH4H2PO4, and H3PO4. The influence of the stripping solution concentration on the desorption characteristics of an inactive HCO3 ion into a stripping solution from IRN-150 mixed resin and the gasification of this ion to CO2 is analyzed. The gasification behavior to CO2 using NaOH, HNO3, and HCl was also compared to that of phosphate solution. Spent resin stored in Wolsong nuclear power plant is used to evaluate the gasification characteristics of 14C radionuclide to 14CO2. Gamma radionuclides such as 137Cs and 60Co in residual striping solutions after desorption experiments are analyzed.