Objective To analyze the fermentation process and antioxidant activity of Anoectochilus roxburghii (Wall.) Lindl using Lactobacillus plantarum 191046.Methods A. roxburghii was used as the raw material, and L. plantarum191046 was used as the fermentation strain. The polysaccharide content of A. roxburghii was used as the evaluation index. The fermentation process was optimized by single-factor experiments combined with response surface methodology, and its in vitro antioxidant activity was assessed.Results The optimal fermentation conditions for A. roxburghii were as follows: L. plantarum inoculum of 4.50 g/L, fermentation time of 17 h, and fermentation temperature of 36 ℃. Under these conditions, the polysaccharide content of the fermentation liquid was (24.84±0.05) mg/mL. The total antioxidant capacity was (8.67±0.85) U/mL, the hydroxyl radical scavenging rate was (96.11±0.90)%, the superoxide anion radical scavenging rate for a two-fold dilution was (28.03±2.00)%, and the DPPH radical scavenging rate was (86.13±0.17)%.Conclusion The fermentation of A. roxburghii with L. plantarum 191046 resulted in good antioxidant activity.