The invention discloses a blueberry pretreatment system for preparing a blueberry beverage. The blueberry pretreatment system comprises a juice squeezing barrel with an upper cover, wherein a plurality of liquid leakage holes with small hole diameters are uniformly distributed in the bottom of the juice squeezing barrel; a circular shaft is vertically mounted in the juice squeezing barrel; a rotating shaft being concentric and coaxial with the circular shaft is arranged at the central position of the inner part of the circular shaft; a stirring knife is mounted at the lower end of the rotating shaft; a cavity allowing the stirring knife to be placed is formed in the bottom of the circular shaft, and a through hole allowing the stirring knife to penetrate through the circular shaft downwards is formed in the bottom end of the circular shaft; a baffle is connected to the outer circumference surface of the circular shaft; and the baffle surface of the baffle is perpendicular to a vertical central shaft of the circular shaft. According to the blueberry pretreatment system, fresh blueberries are extruded, loosed and beaten in advance, and squeezed blueberry juice is filtered, so that the blueberry juice does not contain plenty of residues or large peel, is large in amount, and good in mouth feel.