The invention discloses a method for producing a cocktail onion. The method comprises the steps of selecting, cleaning, and pickling the cocktail onion, sealing a pickling tank, washing and squeezing the pickled cocktail onion to be dry, proportioning materials, steeping the cocktail onion, draining the steeped cocktail onion, and packing, sterilizing, air drying and boxing the resulting cocktail onion. The proportioning is carried out based on the following mass: 60kg of dry cocktail onion, 40kg of purified water, 2.6-3.5kg of common salt, 9-12kg of white granulated sugar, 2.6-3.4kg of monosodium glutamate, 35-45g of aspartame, 280-320g of acetic acid, 96-110g of citric acid, 16-22g of sodium dehydroacetate, 56-65g of sodium benzoate, 45-55g of D-sodium erythorbate, and 45-55g of disodium diethylamine tetraacetate, and the steeping is carried out. In the production method, the fresh cocktail onion which is symmetric and full in grain is used as a raw material, the cocktail onion is subjected to specific pickling technology and proportioning and steeping steps, the salinity is controlled to be 3-4 DEG to ensure that the produced cocktail onion is a low-salinity food, and the produced cocktail onion is unique in flavor, with agreeable sweetness and agreeable sourness, spicy, tasty, fragrant in onion flavor, and is an instant good table food.