A kind of hierarchical porous silica (HPS) was synthesized in a relatively mild condition and then devoted as the supports to fabricate TEPA-impregnated adsorbents for CO₂ adsorption. HPS has different pore size distribution and the huge pore volume. These structure characteristics of HPS can mitigate the mass transfer resistance which occurs more serious in traditional carrier materials with single smaller channel. The CO₂ adsorption performances of modified HPS were investigated in a homemade fixed bed reactor under different conditions. The HPS exhibited maximum CO₂ adsorption capacities of 5.01 mmol/g when 60 wt.% TEPA loaded. It presented better TEPA loading properties and higher CO₂ adsorption capacities than the majority of the single ordered mesoporous adsorbents according to the literature. When the adsorption experiments were repeated ten times, the amount of CO₂ capture reduces from 5.01 mmol/g to 4.7 mmol/g, only 6.1% reduction. And the deactivation model which can describe the absorption of CO₂ was adopted under different experiment conditions. In all these cases, the experimental data of CO₂ adsorption gave a good agreement with the predicted results by the breakthrough model.