In this work, the solubility of IMP in a water + ethanol system was measured by a gravimetric method at the temperature range from 283.15 to 323.15 K. To explain the solubility behavior of IMP in this system, a model was applied to quantitatively describe the effect of dielectric constants on the solubility of IMP. Then, the induction time was determined to be related to the supersaturation level for analysis of the nucleation mechanism, indicating that homogeneous nucleation dominated the nucleation process at higher supersaturation, while heterogeneous nucleation was more important mechanism at lower supersaturation. Finally, the molecular modeling was carried out to understand the effect of supersaturation on the crystal habits of IMP: the rodlike products preferred to form at high supersaturation, while flakelike products formed at low supersaturation, as shown in the microscopy images. In summary, supersaturation should be considered in the process of optimizing IMP crystallization operation conditions.