The solubility of eszopiclone in four binary solvents (ethanol + water, tetrahydrofuran + water, acetonitrile + water, acetone + water) at the temperature range of T (288.15-328.15) K was determined with the gravimetric method. The experimental results showed that the solubility of eszopiclone increased as temperature rose. It was observed that the solubility varied in the binary solvent systems with the change in the fraction of water. The dissolution ability of the aqueous solvent mixtures was obviously improved with the added water. The characterization of the solid samples with X-ray powder diffraction showed that the crystal form of eszopiclone remained stable in this experiment. The increase of solubility in a binary solvent system may be related to the effect of a hydrogen bond. The experimental solubility data were correlated with the solvent composition and temperature using the CNIBS/R-K model and the Jouyban-Acree model. It was found that the calculated solubility was consistent with the experimental data. These results could give guidance to practical industrial processes such as the design of a crystallization process.