The ratio of raw material to water,the temperature and the proportion of enzyme in coix seed hydrolysis were determined according to the values of DE.The ratio of raw material to water,the temperature and the time duration in buckwheat extracts were determined according to the soluble solid contents.With coix seed juice,buckwheat juice,high fructose syrup,citric acid,and water as experimental factors,with sensory quality evaluation as index,the best formula of the mixed juice was determined by mixture design.With guar gum,xanthan gum,sodium alginate and monoglyceride as experimental factors,with viscosity,centrifugal separation percentage,and standing layered percentage as indexes,the optimum compound stabilizers were also determined through orthogonal experiment.The results showed that the optimal parameters of hydrolysis of coix seed were: the ratio of raw material to water 1∶ 10,temperature 500°C and the proportion of enzyme of 0.06g/10g.The optimal parameters of extraction of buckwheat were: the ratio of raw material to water 1∶ 10,800°C for 60min.The best formula of the compound juice was coix seed juice 30%,buckwheat juice 5%,high fructose syrup 5%,and water 60%.Guar gum,xanthan gum and sodium alginate were compound stabilizer with monoglyceride as emulsifier at the concentration of 0.06%,0.05%,0.06%,0.30%,respectively.