Abstract: The toxicity of Thifluzamide, Epoxiconazole and their mixtures were tested by hypha growth rate on Rhizoctonia solani Kühn, in order to determine the combined effect of the mixtures. The results showed that, the EC50 of the mixtures at the ratio of 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4 was 0.1188, 0.0897, 0.0483, 0.0387, 0.1220, 0.0997, 0.0569, 0.0813 μg/mL, respectively. And the SR was 0.79, 1.01, 1.77, 2.02, 0.60, 0.67, 0.97, 0.66, respectively. The biological activity of Epoxiconazole on Rhizoctonia solani Kühn was higher than that of Thifluzamide. The mixtures at the ratio of 3:1 and 2:1 have synergism on Rhizoctonia solani Kühn.