Abstract: Objective To deter mine the pulmonary injury of dominant indoor airbor ne fungi on the rats and analyze its mechanisms.Methods Inoculated viatrachea with fungi suspension,SD rats were used to observe the adverse effects of fungi on the respiratory tract system.Bronchoalv eolar lavage fluid(BALF)were analyzed to determine the injury on lung.Results The levels of LDH、ACP、AKP were significantly higher than control group and dose-respo nse relationships were observed,and lung oxygen free radicals in the administered group were higher too.Conclusion The dominant indoor airborne fungi could have the pulmonary-injury effects on the rats,and of oxygen in lung tissue free-radicals-might be under lying mechanism.