Abstract: Tier I Eco-Risk Calculator was used to predict the risks of diazinon 500 EC to Japanese Quail (Coturnix japonica) basing on the results of in-door acute toxicity tests.The acute toxicity tests showed that the oral LD50 of diazinon 500 EC to C.japonica is 4.61 mg per 1 kg body weight,and the dietary LC50 of diazinon 500 EC to C.japonica is 120 mg per 1 kg diet.The output of model showed that,for seed treatment,diazinon posed a highly acute risk to birds by oral exposure.For application of spray on crops,by the dietary exposure,the risk of diazinon to birds was also high.Therefore,mitigation measures were discussed in order to reduce its risk to birds.And the adoptable measures include:prohibit from applying in or near the Birds Nature Reserves;reduce the application rate,change the formulation or using method were proposed under the condition of not influencing the efficacy.