Abstract: The soft soils can meet the bearing needs of the constructions and infrastructures through the appropriate artificial treatment, and the carbonated MgO-mixing pile method is an innovative foundation treatment technology, which is that the reactive MgO-mixing pile takes a series of physical and chemical reactions with CO₂ gas, forming a composite foundation with good stability and high bearing capacity. On this basis, the indoor mixing pile model tests are carried out under different initial water contents and different CO₂ ventilation pressures by use of the artificial dig-hole pile method, and the temperature of mixing piles is monitored during the carbonation process, as well as these tests are performed after carbonation including unconfined compressive strength and water content. The results indicate that the pile temperature can reach the highest in less than two hours’ carbonation, and the temperature peak is the highest at the initial water content of 20%, the second at 15% and the lowest at 30%. The temperature peak increases with the increase of CO₂ ventilation pressure. The strength of carbonated piles decreases with the increase of the initial water content while increases with the increase of the CO₂ ventilation pressure, and the strength decreases with the water content of the carbonated soils in the form of exponential function. The carbonated mixing-pile model tests will provide theoretical guidance for the MgO-carbonation technology in the engineering application of soft soil foundation reinforcement.