Abstract: Rice blast and sheath blight are very important fungal diseases in rice, and one of the main measures to control these diseases is chemical control. The paper aims to select the fungicides with strong toxicity against Magnaporthe oryzae and Rhizoctonia solani by indoor toxicity determination. The toxicity of 7 fungicidesagainstM. oryzae andR. solani wasdeterminedbythemycelialgrowthratemethodinthelaboratory.The results showed that: 6.25% Fluindapyr (codenamed IR9792) EC had the strongest toxicity with EC50 1.01 mg/L, against M. oryzae in the 3 succinate dehydrogenase inhibitor (SDHI) fungicides; 25% pyraclostrobin EC had the highest toxicity with EC50 0.01 mg/L in 3 kinds of Strobilurin fungicides against M. oryzae; the EC50 of 48% prothioconazole SC, a Triazole thione fungicide, against M. oryzae was 0.70 mg/L; to R. solani, 24% thifluzamide SC, a (SDHI) fungicide, had the highest toxicity with EC50 0.07 mg/L; the toxicity of 20% coumoxystrobin SC against R. solani was 0.52 mg/L; the EC50 of 48% prothioconazole SC against R. solani was 1.19 mg/L. These results provide a basis for further development and application of the above fungicides.