The invention mainly belongs to the technical field of grease processing, and discloses a preparation method of selenium-enriched Sichuan pepper oil. The preparation method comprises steps of raw material preparation, fermentation, drying, heating, deep frying, and packaging. The preparation method is simple; operation is convenient; the obtained Sichuan pepper oil is thick in flavor, fresh, golden yellow, and slightly pungent; no additive is added; the selenium-enriched Sichuan pepper oil is safe and good for health; the variety of commercial Sichuan pepper oil is increased; requirements of consumers on nutrients and mouthfeel are satisfied. According to the preparation method, a white granulated sugar solution is added into Sichuan pepper firstly, inoculation with Angel saccharomyces cerevisiae is carried out to promote bacteria proliferation, protein selenium is added for low temperature long term fermentation, so that full leaching of effective components in Sichuan pepper seeds and leaves is realized, fragrance and oil yield are improved, selenium content is increased, and Sichuan pepper oil health care functions are improved; plant oil is heated to remove raw oil smell, natural cooling is carried out, and then dried Sichuan pepper is added for deep frying, so that generation of scorched smell is avoided, the obtained product is safe and good for health, water in Sichuan pepper is removed completely, grease and flavor ingredients in Sichuan pepper are extracted, Sichuan pepper oil oxidative rancidity is avoided, and self life is prolonged.