The endophytic fungus was isolated from Pseudostellaria heterophylla roots to study the scavenging capacities of different polar extracts of its fermentations on diphenyl picrylhydrazyl(DPPH) radical and hydroxyl radical(·OH),and the contents of total polyphenols for different polar extracts were also determined.The results showed that only one strain named NSZJ-1 was the non-pathogenic endophyte among ten endophytic fungi achieved.Strain NSZJ-1 was confirmed as Cylindrocarpon sp. based on the morphological observation and molecular identification.The IC₅₀ values of five different polar solvent extracts,viz.petroleum ether,dichloromethane, ethyl acetate,n-butanol and ethanol of strain NSZJ-1 fermentation broth for scavenging DPPH and ·OH radicals were 270.537, 27.189,2.061,0.672,6.181 mg/mL and 946.221,39.957,9.466,1.053 and 11.270 mg/mL,respectively.The contents of total polyphenols in five different polar solvent extracts,viz.petroleum ether,dichloromethane,ethyl acetate,n-butanol,and ethanol were 0,0.002 9,0.005 5,0.018 6,0.011 1 mg/mL,respectively.This study indicated that the endophytic NSZJ-1 could be used as a resource of antioxidant ingredients for development and research.