To explore the effect of returning crop straw to the field structure improvement. In this experiment,we adopted in two factor split plot design that of main factor fertilization (F): F1 (NPK compound fertilizer),F0 (no fertilizer); and that of the auxiliary factor crops (B): B1 (rape),B2 (corn),B3 (potato),B4 (oats),B5 (buckwheat). Unplanted and without fertilization used as the control (CK). We measured several parameters that of soil bulk density,porosity,capillary porosity,field water holding capacity,aggregate size and MWD,GMD,D values. The results showed that straw mulching of 5 crops reduced soil bulk density,increased capillary porosity and field water retention in 0—60 cm soil layer,and 20—60 cm soil layer was the main improvement. At the same time,the content of soil >0.25 mm granular aggregates was increased,and the MWD and GMD values of aggregates in the 0—20 cm soil layer were increased,while the D values were decreased and the stability was increased. When straw was returned to the field with chemical fertilizer,the content of >0.25 mm granular aggregates in 0—60 cm soil decreased,MWD and GMD values decreased,and D values increased,and the stability decreased. We confirmed that rape straw returned treatment would improving soil density,porosity,filed water-holding capacity and aggregate stability,buckwheat straw returned treatment would increasing filed water-holding capacity,oat straw returned treatment would increasing soil aggregate stability. We concluded that returning crop straw to field would improving the soil structure and achieved different effects to differ crop types. In general,the rape straw returning to field is better improvement for soil structure.