▎ 摘　　要

NOVELTY - Catalyst comprises a carrier, an active component and a heat-conducting material. The active component comprises a main active component and an auxiliary agent. The main active component comprises a vanadium compound and optionally a phosphorus compound and a cesium compound. USE - The catalyst is useful for preparing phthalic anhydride by oxidation of o-xylene (claimed). ADVANTAGE - The catalyst: can provide strong exothermic section for the production of phthalic anhydride by oxidation of o-xylene which is added with an specific amount of materials with good heat transfer performance and conducive to rapid heat transfer and removal; evaluates on a 2000 ml bed; has molten salt temperature of 343 degrees C; and produces phthalic anhydride using 109g/Nm3 o-xylene, and with mass yield of 118.78%. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) preparing a catalyst, comprising (i) mixing the mixed solution and titanium dioxide, auxiliary agent, heat-conducting material and adhesive to obtain the catalytic active component slurry, preferably the mixed solution comprises solvent, reducing agent and main active component and the viscosity of the slurry is 10-40 Pa.S, more preferably 12-25 Pa.S, and (ii) spraying the slurry of the catalytic active component on the carrier and drying; and (2) preparing phthalic anhydride by oxidation of o-xylene, comprising passing the mixed gas containing o-xylene into a fixed bed reactor for reaction along the direction from the inlet to the outlet of the mixed gas containing o-xylene, where the fixed-bed reactor comprises A-stage catalyst, B-stage catalyst, C-stage catalyst and D-stage catalyst which are sequentially packed, preferably the A-stage catalyst is the catalyst as specified above.