Abstract: The main peach cultivar of ‘Yanhong’ was used as a control, soluble sugar and organic acid content in eight local peach cultivars from Guizhou Province were measured by high performance liquid chromatography (HPLC). The indexes were then analyzed to evaluate the quality of their sweet-sour flavor. Results showed that (1) soluble sugars in the flesh of the eight local peaches included sucrose, glucose, fructose and sorbitol. The content of sucrose was the highest (mean content 55.62 mg/g), accounting for 71.30% of total sugar, but the coefficient of the cultivars was only 17.92%; Except for ‘Mi’, the glucose and fructose contents in the seven other peaches were similar, and the ratios of fructose to glucose in ‘Mi’ were 1.21. (2) Organic acid in the flesh of the eight local peaches included malic acid, citric acid, quinic and shikimic acid. The content of malic acid was the highest, accounting for 60.61% of total acid, although the content of quinic acid was highest in ‘Baihua’. (3) The soluble sugar and organic acid content data were processed by principal component analysis (PCA), which showed that the load coefficients of malic acid and sorbitol were 0.910 and 0.897, respectively. They were the major influencing factors on the flavor of sour-sweet in the peaches, and also played an important role in improving the sour-sweet flavor quality. The fruit flavor of ‘Huangla’ was sweet, ‘Xie’, ‘Qing’, ‘Zhenyuan’ and ‘Hongfeng’ were sweet and sour, and ‘Baihua’, ‘Xi’ and ‘Mi’ were sour.