PURPOSE: A functional composition containing subcritical water extract of apple peel is provided to enhance antioxidation effect. CONSTITUTION: A method for preparing subcritical water extract of apple peel comprises: a step of drying the apple peel by hot wind; a step of mixing the dry apple peel powder and diatomite in weight ratio of 1:2; a step of putting the mixture in a subcritical water extractor; and a step of extracting the apple peel at 1300 psi and 110-190 Deg. C. for 10 minutes and drying. A functional composition for antioxidation contains the subcritical water extract as an active ingredient. [Reference numerals] (AA)[Annotation]