Abstract: The antifungal and herbicidal activity of 11 strains of endophytic fungi ( J46, J77, J80, J85, J86, J94, Y51, Y52, Y57, Y125, Y127 ) from Oriental Arborvitae against the mycelium growth of 12 kinds of plant pathogenic fungi and seed germination of Amranthus retroflexus were tested respectively. The results showed that the inhibition rate of 10 strains of endophytic fungi were more than 50% at least to one pathogenic fungus. There were 5 strains of endophytic fungi ( Y52, J94, Y127, J77 and J46) whose inhibition rate against Valsa mali were more than 70%, and 4 strains of endophytic fungi (J94, Y52, J77 and J46) whose inhibition rate against Botrytis cinerea were more than 70%. The endophytic fungi displayed strong inhibition to the radicle of A. retroflexus, in which inhibition rate of 8 strains were more than 70%. ITS sequence was determined to classify the 8 strains of endophytic fungi with good antifungal or herbicidal activity, and it showed that they were all Alternaria alternaria.