Abstract: A supported oxidant CrO₃/SiO₂ was prepared by absorbing the CrO₃ on silicon gel, and its oxidation characteristics was investigated for the oxidation of N-benzoyl-dehydroabietylamine to N-benzoyl-dehydroabietylamine-7-one in this paper. Effects of solvent types and quantities, reaction temperature, loading amount and oxidant dosage on the yield were examined. The test result indicated that N-benzoyl-dehydroabietylamine-7-one can be obtained with yield of 60% by oxidation of 1 g(2.57 mmol)N-benzoyl-dehydroabietylamine in the present of 2 equimolar amount of CrO₃/SiO₂(loading amount 2 mmol/g)in 50 mL cyclohexane under the reflux temperature for 8 h. This reagent is easily prepared, it can be used in the field of allylic oxidation in relatively high oxidation selectivity, yields with simple procedure and easy purifications.