Objective In order to reduce the toxicity and still maintain the bioactivity of the medicinal plant Tripterygium wilfordii(TW),the whole plant biotransfomed method was employed.By observing the pharmacological activities and the toxicity of MeOH extracts from the root of T.wilfordii that were biotransformed by the fungi Aspergillums spp.and Rhizopus spp.,the best biotransformed fungi strain has been selected based on the experimental data.Methods Applying the models of acute and chronic inflammation, the weight of immune organ and cell immunity were used to study the pharmacological activities,and ip injection to observe the acute toxicity.Results The anti-inflammation and immunosuppression have been increased slightly and the toxicity decreased significantly after being biotransformed by Aspergillus spp.(TW1),while the anti-inflammation,immunosuppression,and the toxicity have been declined after being biotransformed by Rhizopus spp.(TW2).Conclusion Although both selected fungi could change the pharmacological activities and toxicity of the T.wilfordii,Aspergillus spp.is better than Rhizopus spp.