Abstract: In this study, Huangguan pears were used as experimental materials, and the sulfur-free color protectors including citric acid, ascorbic acid and D-isoascorbate sodium were employed to inhibit the browning. Then, the optimal formula combination of sulfur-free color protectants was determined through single factor experiment and response surface design. Results showed that these color protectants could all effectively inhibit the browning of Huangguan pear juice, especially citric acid, and ascorbic acid second. The best compound formula for color protection was determined as follows: citric acid of 0.22%, ascorbic acid of 0.15% and D-isoascorbate sodium of0.50%. The browning degree of huangguan pear juice was 0.813 2±0.052 1 using the color protector formula, which was close to the predicted value.