ZrO₂/PO₄^-3 and ZrO₂/BO₃^-3 catalysts were prepared by precipitation from the solution of zirconium oxychloride followed by modification with phosphoric acid and boric acid, respectively. The characterization of prepared catalysts was examined by infrared spectra, X-ray diffraction and differential thermal analysis. On the basis of the results obtained from X-ray diffraction and DTA for ZrO₂ modified with acids, the transition temperature from amorphous to tetragonal phase was high by 150-200℃ and the specific surface increased by about 40-50m²/g, as compared with pure ZrO₂. The acid strength of modified catalysts increased by 2.6-5.2 unit as Ho scale.