The aim of this study was to screen the representative indexes of melon nutritional quality and identify the nutritional quality characteristics of different varieties of melon. Based on the data of 18 nutritional quality indexes of melon, the principal component analysis (PCA) was used to select the representative indexes of melon quality. The results showed that the loading values of ash, fat, V_B1, niacin, tartaric acid, sucrose, total sugar, soluble solids and total acid in the corresponding principal components of the 18 indexes were relatively high, which could better reflect the overall variation of the data. The 13 kinds of melon can be grouped into 2 groups. The second category was represented by Jiashi Gua and Xizhou Mi 25. In conclusion, ash, fat, V_B1, niacin, tartaric acid, sucrose, total sugar, soluble solids, and total acid could be used as the representative characterization indexes of melon quality characteristics. One kind of melon, represented by 86, was rich in ash, V_B1, niacin, tartaric acid, sucrose, total sugar, and soluble solids. The melon of Jiashi type was rich in fat and total acid. The results of this study could provide a characteristic index basis for evaluating the nutritional quality of melon and lay a foundation for the subsequent classification and classification of melon.