Abstract: 【Objective】 To make clear the nutrition quality and evaluation indices of different varieties of watermelon. 【Method】16 components in 6 varieties watermelon were determined, the nutrition quality differences of components in varieties were studied by INQ (index of nutrition quality), and furthermore, though principal component analysis, the nutrition quality evaluation indices of watermelon were screened. 【Result】The results showed that the INQ of nicotinic acid, sodium, fat, zinc were lower than 1, the INQ of carbohydrate was 1.38~1.44, the INQs of potassium and VB₂ were higher than 2, the INQs of manganese, VB₁, protein, ferrum, calcium, cuprum, fiber, phosphorus, magnesium were different because of varieties, and among them, the loadings of magnesium, VB1, manganese, ferrum were relatively high. 【Conclusion】VB1, protein, fiber, manganese, ferrum, calcium, cuprum, phosphorus and magnesium embody the difference among varieties reflecting nutritional quality of watermelon, and among them, VB1,manganese, ferrum can be used as nutrition quality evaluation indices of watermelon.