In this paper， Dendrobium huoshanense was used as raw material to study the changes of active components (total phenols， total flavonoids， and total acids) and in vitro antioxidant properties (ABTS radical scavenging capacity and hydroxyl radical scavenging capacity) during fermentation. The correlation between the changes of active components and in vitro antioxidant properties was determined by Spearman analysis. The oxidative stress model was constructed with WRL-68 human normal hepatocytes to explore the changes of cell-related antioxidant enzyme activities before and after fermentation. The results showed that the contents of total phenols and flavonoids of Dendrobium huoshanense enzyme increased by 35.5% (P < 0.05) and 49.1% (P < 0.05)， and the scavenging capacity of ABTS· and ·OH increased by 31.1% and 26.3%， respectively. The former was positively correlated with the contents of total phenols (P < 0.01) and total acids(P < 0.05)， while the latter was positively correlated with the contents of total acids (P < 0.01) and total flavonoids (P < 0.01). The oxidative stress model of WRL-68 cells was constructed with hydrogen peroxide. In the enzyme group， the level of intracellular reactive oxygen species (ROS) decreased significantly， and the activities of related antioxidant enzymes catalase (CAT)， glutathione peroxidase (GSH-Px)， and superoxide dismutase (SOD) increased. Conclusion: the active components and antioxidant capacity of Dendrobium huoshanense before and after fermentation were significantly improved， and the improvement of antioxidant capacity was significantly positively correlated with the increase of phenolic acids and flavonoids during fermentation. After fermentation， WRL-68 cells had a stronger protective ability against oxidative stress than before fermentation.