With the aid of a laser monitoring technique, the solution thermodynamics of diflufenican was sysmatically studied in the pure and binary solvent systems. The solubility screening results showed that diflufenican had excellent solubility in ethyl acetate, acetone, benzene, and toluene which could be used as good solvents. While methanol, ethanol, isopropyl alcohol and cyclohexane were the poor solvents for diflufenican as the solubility was quite small. Two binary solvent systems (acetone + water, acetone + ethanol) were composed, which exhibited a wide solubility range of diflufenican. The solubility data were well correlated by the modified Apelblat model, NRTL model, van't Hoff model, Ah model, and Jouyban Acree model, which provided the basis for the design and optimization for the diflufenican crystallization process.