It has been determined that Lycium barbarum L. leaves are a vital source of bioactive chemicals and have good potential for creating nutritious formulations. In this work, gavage injections of Lycium barbarum L. leaves flavonoids (LBLF) at various doses -50, 150, and 300 mg/kg BW -were administered to Sprague-Dawley (SD) rats. Four main LBLFs (rutin, chlorogenic acid, kaempferol, and quercetin) were assessed for stability and antioxidant activity in vivo. The findings demonstrated that within 4 h of the LBLF intervention, the plasma levels of rutin, chlorogenic acid, kaempferol, and quercetin were significantly dose-dependent. The rutin content peaked at 762.16 ± 36.63 μg/g at 1 h after the intervention, while the other three peaked at 383.07 ± 3.19 μg/g, 29.44 ± 1.95 μg/g and 18.511 ± 1.99 μg/g, at 3 h after the intervention respectively. Additionally, the levels of malondialdehyde (MDA) were significantly lower, and the activities of glutathione peroxidase (GSH-P x ), catalase (CAT), and total superoxide dismutase (T-SOD) were all considerably higher than those of the control group. This will establish a basis for elucidating the LBLF metabolic pathway in vivo, additional research into techniques to increase its stability, and investigation into its therapeutic activity.