The total phenolic content,total flavonoid content,antioxidant activity,and nitrosation activity of different solvent extract from Pyrrosia lingua (Thunb.) Farwell were compared and analyzed for correlation.The contents of total phenolic and total flavonoid from P. lingua were determined by Folin-Ciocalteu colorimetric method and Al(NO₃)₃ complexation spectrophotometric method.DPPH,ABTS,and Prussian blue method were used to determine the free radical scavenging and iron reducing power of extracts from P. lingua.The removal rate of nitrite and the blocking rate of nitrosamine synthesis were determined by naphthylethylenediamine hydrochloride method and α-naphthylamine method,and Pearson correlation analysis method was used to measure their relationships.The results showed that there were significant differences in the contents of total phenolics and total flavonoids among different solvent extracts.The N-butyl alcohol phase contained the highest amount of total phenolics 29.85±2.15 mg/g and total flavonoids 37.23±2.41 mg/g.All the extracts showed strong antioxidant and nitrosation activity.The N-butyl alcohol phase also had the highest antioxidant activity and inhibitory activity among the four extracts (P<0.05),which showed DPPH radical scavenging activity(IC₅₀=44.14±1.21 μg/mL),ABTS radical scavenging activity(IC₅₀=97.47±12.10 μg/mL),reducing ferric(822.08±24.82 μmoL Vc/g),scavenging rate for nitrate(IC₅₀=7.071±0.231 mg/mL) and blocking rate of nitrosamine(IC₅₀=15.010±1.224 mg/mL),and were significantly stronger than those of other extracts(P<0.05).The results of correlation analysis showed that there were significant correlations between the contents of total phenolic and total flavonoids and antioxidant activity,inhibitory activity on nitrosation(P<0.05) of all extracts,and the material basis of antioxidant activity inhibitory activity on nitrosation of P. lingua may be phenolics and flavonoids.The evaluation of index components,activities,and related analysis of different solvent extract from P. lingua will provide experimental data for quality evaluation and rational utilization of P. lingua.