CO2 capture is very essential to mitigate the greenhouse gas control. However, the CO2 desorption is quite costly during CO2 capture. To reduce the cost, the CO2 desorption integrated with coal flotation was developed as a retrofitted process, which can simultaneously achieve the CO2 desorption and coal flotation. To determine the key interactive effects between coal, amine, and CO2 in the process, a high-order multifield synergy model was developed accordingly. According to the high-order multifield synergy model, the effects of coal particle diameter, coal weight fraction, CO2 loading, and amine on the CO2 desorption and coal flotation were analyzed in detail. It was found that there is almost twice the CO2 amount at coal weight fraction of 0.06 than that at a coal weight fraction of 0.02. The coal recovery rate at 0.35 mol/mol is twice of that at 0.15 mol/mol. The adsorption energy, adsorption layer thickness, and zeta potential determine the interactive effects between coal, amine, and CO2. The coal, amine, and CO2 system increases the coal recovery rate by 25% and reduces the CO2 desorption energy by 20% with desorption temperature below 373 K. The high-order multifield synergy model shows the advantages of higher prediction accuracy and is easier to converge than the conventional multifield synergy model.