In order to clarify the effect of deep tillage on the occurrence of wheat sheath blight（WSB） under the condition of corn straw returning to the field, an experiment was made by potted and field. The result showed that, compared with rotary tillage, except for at the concentration of 5.0 and 2.5 g/mL soil extracts from the deep tillage plow layers in Wangdu, the soil extracts from other deep tillage plow layers all inhibited the growth of R.cerealis mycelium obviously, with the inhibition rates from 3.84% to 28.19%. After treatment with 1.25, 0.625 and 0.3125 g/mL soil extracts from deep plow layer in Wangdu experimental base, the number of sclerotia decreased by 16.18%～33.62%.There was no significant difference on the fresh weight of sclerotia between the deep tillage（except for at the concentration of 5 g/mL） and rotary tiller at the same plowing layer. After irrigating the soil extracts from deep tillage plow layers in Gu'an at the concentration of 2.5 g/mL, the disease index of WSB was from 18.84 to 28.72, which was significantly lower than that of rotary tillage. At the Jointing stage, deep tillage could significantly reduce the WSB incidence with a decrease about 15%, but the disease index didn’t change significantly.