Objective: This study aimed to improve the flavor and solubility of extruded corn flour by compounding. Methods: D-optimal mixture design was used to add different proportions of puffed millet flour, fried red rice flour, puffed rice flour, and puffed black rice flour, into puffed corn flour. The composite powder was analyzed and evaluated from the perspectives of caking rate, viscosity, sensory score, and volatile flavor substance changes. The aroma components of different samples were analyzed by gas chromatography-mass spectrometry. Results: The formula of compound powder was as follows: expanded corn flour 50.8%, expanded millet flour 8.8%, fried red rice flour 0.5%, expanded rice flour 19.9%, and expanded black rice flour 20.0%. Compared with the single extruded corn flour, the caking rate of the composite powder was reduced to 0.52%, the viscosity was increased to 2 880 mPa·s, the sensory score was 87.84 points, and the blending performance was also significantly improved. The flavor substances in the compounded extruded corn flour, such as a green aroma and a nut aroma was increased. To be noticed, the increasing of aldehydes is the most obvious. Conclusion: The quality of the compounded extruded corn flour was improved, and the volatile flavor substances were increased.