In this research, the solid liquid equilibrium solubility of diclazuril was measured by the isothermal saturation method, and the influence of the solvent effect on solubility was discussed. In monosolvents, at the determined temperature, the solubility values of diclazuril decrease according to the order: dimethylformamide (DMF) > acetone > acetonitrile > ethyl acetate > methanol > ethanol > 1-propanol > 2-propanol > 1-butanol > toluene. Besides, in two binary solvent mixtures, the solubility increases with the increasing ratio of DMF/acetone and decreases with the increase of ethanol. What is more, five models including modified Apelblat equation, lambda h equation, Jouyban-Acree model, van't Hoff-Jouyban-Acree model, and Apelblat-Jouyban-Acree model were used to correlate the diclazuril solubility in monosolvents and binary solvent mixture systems. The relative average deviation and root-mean-square deviation values were no more than 0.97% and 6.95 x 10(-4), respectively. All these five models can correlate the solubility values of diclazuril very well. Ultimately, the experimental data presented in this study can provide basic data for improving the solubility of diclazuril.