The Solubility of luteolin in ethanol + water was measured at (273.15 to 323.15) K using high-performance liquid chromatography (HPLC). The solubility of luteolin in ethanol + water mixed solvents presents a maximum-solubility effect. The modified Apelblat equation was used to correlate the experimental data and exhibited good agreement. A relatively appropriate process was given for the purification of luteolin, with rutin as an impurity.