The solution redistribution was an important phenomenon during the solidification of multi-component alloys. The improvements of the solute redistribution were considered in this paper especial in the simulation processes. The models of Gibbs free energy were taken into three kinds such as pure materials, the substitutional solution and the sublattice. Calculating the Gibbs free energy of the system, the solute redistribution coefficients could be calculated. The simulated results of Al-Cu binary and Al-Si-Mg ternary alloys agree well with the experimental results.