Abstract:To develop a novel compound fermented Milk，this study utilized red coix seed and milk powder as the primary fermentation substrates，with the addition of green tea，and employed lactic acid bacteria for fermentation. The enzymatic hydrolysis process of red coix seed pulp and the preparation method of green tea juice were investigated. Through single-factor and orthogonal tests，the optimal fermentation process and formulation for the product were determined. The results showed that the optimal enzyme-substrate ratio for preparing red coix seed juice is 300∶1 （U/g），and the cold brewing method is adopted for extracting green tea juice.The optimal fermentation conditions were as follows：a fermentation time of 8 h，a fermentation temperature of 44 ℃，and an inoculation amount of lactic acid bacteria at 0.20%. The optimal formulation consisted of 25% red coix seed pulp，7% sucrose，12% milk powder，and 10% green tea juice. Under these conditions，the product exhibited a uniform and smooth texture，with balanced acidity and sweetness，and a rich milky aroma complemented by a refreshing green tea flavor，demonstrating excellent quality.