In order to fully understand the variations of fruit quality-related phytochemical composition in Chinese bayberry (Myrica rubra Sieb. et Zucc.), mature fruit of 17 cultivars from Zhejiang and Jiangsu provinces was used for the investigation of fruit quality attributes, including fruit color, soluble sugars, organic acids, total phenolics, flavonoids, antioxidant capacity, etc. Sucrose was the main soluble sugar, while citric acid was the main organic acid in bayberry fruit. The content of total phenolics and total flavonoids were positively correlated with 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) antioxidant activity and 2,2MODIFIER LETTER PRIME-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activity. Five anthocyanidins, i.e., delphinidin-hexoside (Dp-Hex), cyanidin-3-O-galactoside (C-3-Gal), cyanidin-3-O-glucoside (C-3-Glu), pelargonidin-3-O-glucoside (Pg-3-Glu) and peonidin-3-O-glucoside (Pn-3-Glu), and seven flavonols compounds, i.e., myricetin-3-O-rhamnoside (M-3-Rha), myricetin deoxyhexoside-gallate (M-DH-G), quercetin-3-O-galactoside (Q-3-Gal), quercetin-3-O-glucoside (Q-3-Glu), quercetin-3-O-rhamnoside (Q-3-Rha), kaempferol-3-O-galactoside (K-3-Gal) and kaempferol-3-O-glucoside (K-3-Glu), were identified and characterized among the cultivars. The significant differences in phytochemical compositions among cultivars reflect the diversity in bayberry germplasm, and cultivars of good flavor and/or rich in various health-promoting phytochemicals are good candidates for future genetic breeding of bayberry fruit of high quality. In conclusion, our results may provide important information for further breeding or industrial utilization of different bayberry resources.