Abstract: In order to measure the Kr and Xe isotopes of trace-level radioactive gases in large volume gas, the mixed gas must be concentrated and adsorbed in the activated carbon source box of about 10 mL. In this experiment, the adsorption properties of components in the mixed gas on the activated carbon column were studied. The method of the separation of other impurity gases and the concentration of large volume gas was established. According to the understanding of possible gas composition of effluent gas from reactor and nuclear explosion, the simulated gas containing water, CO₂, H₂, CO, CH₄, Kr and Xe was prepared. The activated 4A molecular sieve was used to remove the water and CO₂. The adsorption characteristics of H₂, CO, CH₄, Kr and Xe were studied on the fully cooled activated carbon column. The breakthrough curves of H₂, CO, CH₄, Kr and Xe gases at different temperatures were measured. The results show that 4A molecular sieve has large adsorption capacity for water and CO₂ at room temperature. At low temperature, H₂ and CO are not easily adsorbed on the surface of activated carbon. CH₄ and Kr have similar adsorption properties, and Xe has strong adsorption capacity. CH₄ which is difficult to remove at low temperature can be oxidized and removed at high temperature. Therefore, according to the different properties of each component in the mixed gases, the removal of impurity gases and the recovery and measurement of target gases Kr and Xe can be realized.