Abstract: Objective:To analyze the constituents,anti-oxidant and antibacterial properties of volatile oil from Selaginella uncinata. Methods:GC-MS was used to separate and identify the chemical components of the volatile oil of Selaginella uncinata. DPPH,FRAP and chelation of metal ions were used to evaluate the antioxidant activity of the volatile oil of Selaginella uncinata in vitro. Paper diffusion method was used to determine the antibacterial activity of volatile oil of Selaginella uncinata,including three Gram-positive bacteria,namely Staphylococcus aureus,Enterococcus faecalis and Corynebacterium pyogenes,and three kinds of Gram-negative bacteria,namely Escherichia coli,Pseudomonas aeruginosa and proteus. Results:52 peaks were isolated and 50 components were identified. The identified components accounted for 98.58% of the total area. The main components were fitone(21.40%),squalene(8.53%),palmitic acid(6.71%),octacosane(6.03%). The IC₅₀ value of DPPH was 0.76 mg/mL,FRAP value of iron ion reduction was 0.86 mmol/L,and EC₅₀ value of metal ion chelation was 0.71 mg/mL. The results of MIC and MBC showed that the volatile oil of Selaginella uncinata had good antibacterial activity against Enterococcus faecalis,Corynebacterium pyogenes,Escherichia coli and Pseudomonas aeruginosa. The MIC value of Enterococcus faecalis was 5 μL/mL,MBC value was 10 μL/mL;the MIC value of Corynebacterium pyogenes was 10 μL/mL,MBC value was 20 μL/mL. Conclusion:In this paper,the volatile oil components of Selaginella uncinata were analyzed by GC-MS,and it was found for the first time that it had certain antioxidant activity and antibacterial activity.