The present invention relates to a pharmaceutical composition containing flavone compound as an active ingredient for treating obesity, and more specifically to a pharmaceutical composition for preventing or treating obesity and a dietary composition for preventing or reducing obesity containing 5,7-dimethoxyflavone or 5,7,4′-trimethoxyflavone. The compound according to the present invention inhibits adipogenesis, and reduces expression of the key transcription factors (SREBP1c and C/EBP) related to lipogenesis and of enzyme proteins (FAS and ACC) related to adipogenesis, and thus is effective in preventing or treating obesity.