Abstract: To achieve efficient CO2 capture from industrial exhaust gases and enhance the resource utilization value of honeycomb coal slag, this study developed a composite adsorbent using honeycomb coal slag as a carrier and monoethanolamine (MEA) as the active component. A porous composite adsorption system was constructed by loading 75% (v/v) MEA solution onto 65-mesh coal slag powder. The surface morphology, elemental composition, mineral structure, and functional groups of the adsorbent were characterized by SEM, EDS, XRD, and FTIR. Using a self-designed fixed-bed reactor, the effects of gas flow rate (0.23-5.00 L/min) and CO2 concentration (400-2000 ppm) on the capture performance were systematically investigated. The cyclic stability was evaluated through thermal regeneration, and practical validation was conducted using real motor vehicle exhaust (containing NOx/SO2). The results showed that under conditions of 5.00 L/min flow rate and nearly 2000 ppm CO2 concentration, the instantaneous capture efficiency reached 86.3%. The maximum capture capacity was 0.04 NL CO2/mL-MEA. Under thermal regeneration at 145 ℃, the CO2 desorption efficiency for simulated flue gas reached 97.9%, and the capture capacity retention rate remained at 70% after 15 cycles. In the real vehicle exhaust test, the CO2 capture capacity reached 0.96 NL CO2 with a single-cycle desorption rate of 90.7%. This study innovatively proposes a low-cost technology for the capture and utilization of CO? from exhaust gases.