Black wolfberry (Lycium ruthenicum, LR) is one of edible and medicinal fruits used widely in West China and contains many nutritional and health benefits of bioactive components. In this study, the phytochemical profiles and nutritional constituents in LR berries from seven production regions were systematically investigated and analyzed quantitatively. And the antioxidant activity of LR berry extracts was also measured by several methods, including DPPH, ABTS, FRAP and ORAC assays. Dietary fibers, soluble sugars, organic acids, minerals and vitamin C were rich in LR berries, and low variation of nutritional constituent contents were detected in these regions. Furthermore, the concentration of the functional components (such as polyphenols, phenolic acids, flavonoids and polysaccharides) varied significantly in LR berries from different regions, and there were no significant differences of these components in the wild and cultivated berries from the same region. Generally, these functional components had significantly positive correlations with antioxidant activity, with exception for total flavonoids and total carotenoids. Overall, LR berries from Qaidam Basin of Qinghai, not only represented abundant nutritional constituents and phenolics, polysaccharides and betaine, but possessed significantly higher antioxidant activity than those of the other production regions, indicating that they can conduct as excellent sources of antioxidants used in nutraceutical formulations and functional foods.