The invention relates to a wild blueberry compound juice and a preparation method thereof. The preparation method comprises the steps of preparing wild blueberry juice and purple sweet potato juice, performing enzyme deactivation to the prepared purple sweet potato juice for 20-30s, mixing the following active ingredients in parts by weight: 10-30 parts of the prepared wild blueberry juice, 2-8 parts of the prepared purple sweet potato juice, 2-15 parts of decolorized deacidified apple concentrated juice, 0.01-0.03 part of xanthan gum, 0.01-0.03 part of sodium carboxymethyl cellulose and 20-50 parts of water, and agitating for 5-8 minutes, thus obtaining the wild blueberry compound juice. By blending the wild blueberry juice, the decolorized deacidified apple concentrated juice and the purple sweet potato juice, the blended compound juice has no acor feeling, is proper in sugar-acid ratio, and appropriate for mouth feeling; without the addition of sweeteners, acidifying agents, coloring matters, essence and the like, the compound juice not only has the fresh aroma of the fresh blueberry fruit, but also has the mellowness of apples, has an unexpectable unique flavor, is natural and delicious, and palatable in acid and sweetness, and has harmonious complex aroma and taste of apples and wild blueberry, thus living up to the consumption conceptions on health and nutrition of the modern people, and meeting the taste of the wide public consumers.