The present invention relates to a preparation method of compound essential oil, which comprises the following preparation steps: taking the following raw materials for use, including Eucalyptus magnanimus essential oil, containing 30%-50% of 1,8-cineole, terpinene-4-alcohol Leaf Melaleuca essential oil tea tree essential oil, containing 4-terpineol 30%-40% (mass fraction); the preparation method of the compound essential oil of the present invention has the characteristics of low toxicity, high efficiency, easy degradation and little environmental pollution, excellent The actual antibacterial effect, the compound essential oil has a pleasant fragrance and a good health care effect, can be used in large quantities in the production of various spices, essences, soaps, cosmetics, food additives, chemical and biological pesticides, etc., can also be developed into similar Essential essential oils, cooling oil, white flower oil, ten drops of water, mosquito repellent oil and other daily necessities suitable for home and travel have good application effects and prospects.