To provide fundamental thermodynamic data for the crystallization separation of succinic acid and adipic acid from mixed dibasic acid, the solubilities of succinic acid in various mass fractions of the adipic acid + glutaric acid + acetone mixture and adipic acid in various mass fractions of the succinic acid + glutaric acid + acetone mixture were measured by the dynamic method at a temperature range of 277.85327.95 K under atmospheric pressure. The results showed that the solubility of succinic acid in acetone increased with increasing mass fraction of adipic acid and glutaric acid in the mixed solvent at the same temperature. Similarly, the solubility of adipic acid in acetone increased with increasing mass fraction of succinic acid and glutaric acid in the mixed solvent at the same temperature. The ideal solution equation, Apelblat equation, lambda h equation, and nonrandom two-liquid (NRTL) equation were applied to correlate the experimental solubility data, which were all in good agreement with the four equations.