Solid-liquid equilibrium (SLE) data were measured experimentally for the ternary system m-cresol + p-cresol + ethylenediamine. These data form a phase diagram in which seven areas were distinguished by the loci of eutectic points. Each region corresponded to a pure or a complex solid that could crystallize from the mother liquor. The phase diagram provided us with the favorable operating conditions for separating m-cresol/p-cresol mixtures by using ethylenediamine;Is a neutralizing agent. The separation strategy was discussed. Moreover, the ideal-chemical model (ICM) and the regular solution-chemical model (RSCM) were applied, respectively, in this study to correlate the binary data and predict the phase behavior of the ternary mixtures.