The invention discloses sleep-promoting nerve-calming pitaya juice and a preparation method thereof and belongs to the field of food processing. The sleep-promoting nerve-calming pitaya juice comprises pitaya, root of red-rooted salvia, Radix Ophiopogonis, a color retention agent, fructose, d-sodium erythorbate and purified water. The sleep-promoting nerve-calming pitaya juice is prepared according to the steps of extracting, cleaning, peeling, crushing, enzyme treatment, pulping, separating, sterilizing and packing. The sleep-promoting nerve-calming pitaya juice has the advantages that the sleep-promoting nerve-calming pitaya juice is mainly prepared from the pitaya supplemented by sleep-promoting nerve-calming traditional Chinese ingredients, thereby having the sleep-promoting nerve-calming effects and nutritional ingredients; the sleep-promoting nerve-calming pitaya juice is simple in preparation technology, long in product expiration date and suitable for large-scale production.