Abstract: MgO-based adsorbents hold broad application prospects in the fields of CO₂ capture and carbon emission reduction. However, traditional shaping methods, such as impregnation, extrusion-rolling, sol-gel, and ball milling, encountered numerous challenges during the industrial scaling-up process. Therefore, there is an urgent need for a technology that facilitates large-scale production. Spray agglomeration is a promising technology, but its applicability in the synthesis of MgO-based adsorbents still requires further validation. The study used commercial magnesium oxide, which was modified by doping with alkali metal nitrate molten salts, to synthesize MgO-based adsorbents with a molar ratio of MgO to alkali metal nitrate molten salts of 1∶0.15 using impregnation and spray agglomeration methods. The CO₂ adsorption performance, surface morphology, and actual molar ratio of the adsorbents were characterized using a micro fluidized bed reactor combined with specific surface area and pore volume, CO₂ temperature-programmed desorption, and scanning electron microscopy. The results showed that under the same component doping conditions, the CO₂ capture capacity of the adsorbents prepared by the spray agglomeration method was superior to that of the impregnation method, especially for the MgO-NaK_0.15-SA adsorbent, which had a CO₂ capture capacity of 4.11 mmol/g in a mixed gas containing 10% CO₂. Further research on the CO₂ capture capacity of MgO-NaK_0.15-SA adsorbent under different conditions showed that the best decarbonization performance of the MgO-NaK_0.15-SA adsorbent was achieved at a reaction temperature of 300 ℃, a CO₂ concentration of 25%, and a mixed gas flow rate of 500 mL/min, with a CO₂ capture capacity of 7.84 mmol/g. The study also investigated the cyclic stability of the MgO-NaK_0.15-SA adsorbent and explained the cyclic decay of the adsorbent by combining specific surface area, pore volume, and actual molar ratio. This study provides new insights and directions for the development and application of efficient MgO-based adsorbents.