Kudingcha is implicated in alleviating metabolic disorders in traditional Chinese medicine. However, the role of Kudingcha, one of the Ligustrum robustum species, in metabolic regulations and its antitumor activity in triple-negative breast cancer (TNBC) remains to be determined. Two breast cancer cell lines and immunocompetent and immunodeficient mice were used to evaluate the therapeutic effects of Kudingcha treatment. The production of reactive oxygen species (ROS) and glucose uptake were examined by flow cytometry. Metabolic shift was examined by metabonomics and western blot analysis. In this study, we found that aqueous extract of Kudingcha dose dependently inhibited cell growth and induced apoptosis in vitro and in vivo. Moreover, Kudingcha supplementation significantly reduced cancer metastasis. Kudingcha significantly inhibited glycolysis and glutamine metabolism. In addition, we demonstrated that the antitumor effects of Kudingcha were dependent on ROS production, which was increased by β-oxidation and oxidative phosphorylation. These findings provide a novel potential benefit of Kudingcha from targeting the cancer metabolism.