This study analyzed the quality characteristics and antioxidant activity of a mixture of apple and carrot juices with different amounts of beet. The pH of the mixed juice sample group increased as the beet amount increased, and the acidity and soluble solid content tended to decrease. As for the L value, the control group was the highest, the beet addition rate decreased, and the a value and b value showed a decreasing trend. As for dietary fiber, B0.1 was found to have the highest dietary fiber content at 0.20 mg/L. As for the mineral, Zn, Fe, and Ca had the highest control group, Mn, Mg, and K had the highest B0.5, and Na and P had the highest B0.1 and B0.3 juices, respectively. Compared to the control group, free sugars increased sucrose as the beet juice added increased. DPPH radical scavenging and total phenol content significantly increased DPPH scavenging as the beet added increased. Therefore, it was found that B0.3 was the most suitable when manufacturing apple and carrot mixed juice with different amounts of beet added, and it is considered as a manufacturing optimization method to improve the marketability and functionality of the product.