The study aims to screen potential anti-inflammatory phytochemicals and explore its mechanism from Tetrastigma hemsleyanum Diels et Gilg based on their molecular docking with Keap1 protein and low-grade inflammatory model of vascular endothelial cells, and further analyzes the effects of active ingredients on the gene and protein expression of pro-inflammatory factors. Results showed that kaempferol-3-O-rutinoside, isoquercitrin, and rutin in root and 5-caffeoylquinic acid, vitexin, and orientin in leaf had significant interactions with Keap1 protein, all of which occurred in the binding cavity of Keap1 with Nrf2 protein, possibly leading to the dissociation of Nrf2 and activation. All of these six phytochemicals could alleviate vascular low-grade inflammation, and among which vitexin had the strongest protective effect. It was further found that vitexin could significantly up-regulate Nrf2 gene and protein expression in cells, while down-regulate Keap1 protein expression, indicating that Nrf2 was activated. In addition, vitexin was highly stable in cell culture medium and buffer salt solution, and it could be absorbed by vascular endothelial cells in a prototype form. Furthermore, vitexin significantly inhibited the gene and protein expression of IL-6, IL-1β, and ICAM, as well as the phosphorylation level of NF-κB p65 in a dose-dependent manner. Therefore, vitexin may have a strong anti-inflammatory function by directly binding with Keap1 to potentially activate Nrf2 and affecting the activity of NF-κB pathway.