Using sour jujube wood chips as raw materials, nitrogen-modified jujube wood based biochars were obtained through urea modification. Based on this, nitrogen alkali coupling modified biochars were successfully obtained through KOH activation. The influence of activation temperature, activation time, and impregnation KOH mass fraction on the comprehensive adsorption performance of coupled modified biochars was investigated through orthogonal experiments. The best performing coupled modified biochar was selected under a simulated power plant flue gas environment (15 vol% CO2, 0.1 MPa, 25 ℃, 2.1 m/min), and its CO2 dynamic adsorption characteristic was studied under varying operating conditions (flue gas temperature, inlet flow rate, and CO2 concentration). Current work indicates that the selected coupled modified biochar exhibited the highest CO2 dynamic adsorption capacity (4.17 mmol/g) under the simulated flue gas environment, with good regeneration characteristic(96.6%) and water resistance(95.4%). Furthermore, the CO2 dynamic adsorption capacity of the selected coupled modified biochar was found to be negatively correlated with adsorption temperature and inlet flow rate, and positively correlated with CO2 concentration. The optimal adsorption conditions identified were adsorption temperature of 25 ℃, intake flow rate of 8.4 m/min, and intake CO2 concentration of 15 vol%. The CO2 dynamic adsorption capacity is 3.59 mmol/g, and the penetration time is 33.8 s.