Abstract: KF/ZnO catalyst was prepared by impregnation and calcination with potassium fluoride as impregnating component and zinc oxide as carrier. The effect of preparation conditions on the methanolysis activity of castor oil of the catalyst was investigated by orthogonal test. The optimized preparation conditions of the KF/ZnO catalyst were found as follows: the mass fraction of KF aqueous solution is 20%, the drying temperature is 150 ℃, the calcination temperature is 450 ℃ and the calcination time is 5 h. The catalyst prepared under optimized conditions is used for methanolysis of castor oil to produce biodiesel, and the conversion rate of castor oil can reach 87.9%. The KF/ZnO catalyst prepared under optimized conditions was characterized by modern characterization techniques. The results show that the KF/ZnO catalyst is composed of supported ZnO crystals and KF and reaction products dispersed in a single layer on the surface. The specific surface area of the catalyst is 8.22 m²/g, the pore volume is 0.019 1 cm³/g, the surface morphology is porous cloud, and the alkali strength is in the range of 7.2 to 15.0.