A method of preparing a patchouli extract is provided and includes the following steps. A patchouli material is grounded into patchouli powder and pelleted to obtain patchouli granules. Liquid carbon dioxide is introduced to perform a supercritical carbon dioxide extraction process on the patchouli granules, wherein the extraction pressure is about 110-180 bar and the extraction temperature is about 40-60℃. During the supercritical carbon dioxide extraction process, the extracted product obtained, based on the total weight of the introduced liquid carbon dioxide not exceeding 10 times the weight of the patchouli granules, is collected as the first patchouli extract, which includes the first patchouli oil. The extracted product obtained, based on the total weight of the introduced liquid carbon dioxide exceeding 10 times but not exceeding 15 times the weight of the patchouli granules, is collected as the second patchouli extract, which includes the second patchouli oil.