Abstract: Four melon varieties with different flesh color： White flesh type, green flesh type, light orange flesh type and orange flesh type were used as materials to study the changes of flesh color and carotenoid content during the development of melon fruit, and to analyze the fitting relationship between a, b of flesh color and carotenoid content. The results showed that the L of light orange red flesh, orange red flesh type and green flesh type melon decreased during the development, and the flesh color became darker; a and b of light orange flesh type, orange flesh type melon continuously increased, and the pulp changed to red and yellow; a and b of green flesh type melon showed a downward trend and changed to yellow-green; L and a of white flesh type melon did not change significantly, but b decreased significantly from 20.9 to 6.3. In orange flesh type melon and light orange flesh type melon, the linear fitting coefficients of carotenoid content and a were 0.773 2 and 0.910 4, and the linear fitting coefficients of carotenoid content and b were 0.882 6 and 0.822 9, respectively, showing a positive and extremely significant correlation. The linear fitting degree of carotenoid content and b of white flesh type melon reached 0.463 7, showing a significant positive correlation. Carotenoid content could be approximately expressed by rapid determination of a and b by color difference meter.

Key words: melon（Cucumis melo L.）, carotenoid, color, correlation coefficient