Abstract: As the most promising thirdgeneration advanced highstrength automotive steels, medium manganese steel features advantages of low cost and high strengthductility synergy. At present, the addition of Al in Fe-C-Mn-Al medium manganese steel achieves lightweighting, optimizes the microstructure, and improves the strengthductility product. Existing micro-segregation models have certain limitations when applied to Fe-C-Mn-Al medium manganese steel. The Leverrule and Scheil models are both idealized models, whereas the Brody-Flemings, Clyne-Kurz, Ohnaka and Voller-Beckermann models incorporate solidphase backdiffusion and can describe the actual solidification process more accurately, among which the Clyne-Kurz model is the most widely used.However, in conventional micro-segregation models, the equilibrium partition coefficient, which is usually treated as a constant, actually varies with temperature(or solid fraction) during real solidification, and the influence of inclusion precipitation should also be considered. By integrating the Clyne-Kurz model, a modified micro-segregation model was proposed that considers the temperature dependent equilibrium partition coefficient and the effect of inclusion precipitation on solute concentration. The solute micro-segregation and inclusion precipitation behavior in Fe-0.15 C-5 Mn-(0.018,0.95,1.93,2.97)Al medium manganese steel were systematically revealed. The results show that, taking the M193 steel as an example, the maximum equilibrium partition coefficient of Al is exceeds the minimum value by 7. 4% during solidification, while that of N reachesas high as 40. 6%.Without considering AlN precipitation, the N concentration increases monotonically with solid fraction during solidification; when AlN precipitation is included, it first rises and then falls. As the Al content increases from 0. 95% to 2. 97%, the amount of AlN precipitated at the solidification end increase from 0. 003 7% to 0. 010 0%. The above conclusions are theoretically significant for controlling the solidification microstructure and inclusions of Fe-C-Mn-Al medium manganese steel.