Abstract: Proposed is an anti-obesity composition containing a hemp seed extract as an active ingredient. Specifically, food and pharmaceutical compositions for preventing or reducing obesity, each of which contains a hemp seed extract as an active ingredient, are proposed. Additionally, proposed is a method of preparing a hemp seed unsaponifiable extract having an anti-obesity activity. The method includes (1) adding a hemp seed, pyrogallol, and potassium hydroxide (KOH) to a reaction vessel and filling the reaction vessel with nitrogen, (2) causing a reaction in a water bath at a temperature in a range of 70° C. to 80° C. for 40 to 60 minutes and then cooling the resulting product, and (3) adding sodium chloride (NaCl) and an extraction solvent in which dibutylhydroxytoluene (BHT) hexane and ethyl acetate are mixed to the cooled product and shaking the resulting mixture to obtain a supernatant.