The cultures from Tripterygium wilfordii were bioassayed with Plutella xylostella insecticidal activity and to reveal the antifungal activity of T.wilfordii adventitious roots.The results showed that all cultures had obvious inhibition and toxicity effect on P.xylostella.The LC₅₀ of suspended cells and adventitious roots are all more than that of root bark,and the LC₅₀ of adventitious roots was 1.95 times of root bark.The extract of different cultures significantly inhibited the growth and development of P.xylostella.After the treatment of the adventitious roots extraction,P.xylostella showed dramatically reduction on body weight,about 70% P.xylostella died after 72 hours and the weight of the survivals decreased by 18.33% after the test.The adventitious roots inhibited the mycelial growth of 11 species of plant-pathogenic fungal in vitro.The inhibition rate of adventitious roots was exceeded 60% of 5 plant-pathogenic fungal species in vitro.It markedly inhibited the mycelial growth of Botrytis cinerea.The EC₅₀ value against B.cinerea was 10.074 mg/mL.The inhibitory effect of adventitious roots was exceeded the root bark in all tests.