[Objective] The effects of different straw returning depths on nutrients and physical characters of yellow brown soil were studied in order to explore the optimal straw returning depth and to provide a scientific basis for improving straw utilization, and soil physical and chemical properties as well.[Methods] This research studied on yellow brown soil, and five treatments of straw returning were set:no straw turning(CK), straw covering surface(T₀), 10 cm-straw turning(T₁₀), 20 cm-straw turning(T₂₀) and 30 cm-straw turning(T₃₀), to analyze soil physical indexes and nutrient contents of 0-40 cm soil layer after wheat harvest.[Results] ① Straw returning decreased the soil bulk density and increased the soil total porosity, saturated water content, field water holding capacity and effective water content. These treatments improved the contents of SOM, AP and total-N in soil by 6.56%~9.96%, 2.81%~7.32% and 1.67%~10.00%, respectively; ② Straw returning treatments decreased the contents of NO₃^--N and NH₄⁺-N by 14.90%~53.42% and 1.48%~15.04%, respectively. There was a significantly negative correlation between NO₃^--N content and the depth of straw returning. ③ The principal component analysis showed that comprehensive score in different straw returning depth treatments decreased in the following order:T₂₀ > T₃₀ > T₁₀ > T₀ > CK, which elucidated that straw returning improved nutrients and physical properties of yellow brown soil, and it showed the most significant depth of straw returning was 20 cm.[Conclusions] If physical properties and nutrient contents were considered, the best depth of straw returning was 20 cm.