Abstract: The paper aims to explore the change of nitrogen, phosphorus and potassium contents after the returning of crop straw biochar and burning, and the effects of straw returning and straw biochar returning of wheat on the yield and the physical and chemical properties of soil in the paddy-upland rotation field and the dry farming area. We measured nitrogen, phosphorus and potassium contents and the loss rate of burning and biochar of rice, rapeseed, wheat and corn straw, and the changes of straw returning and straw biochar returning on the crop yield and the physical and chemical properties of soil. The results showed that nitrogen, phosphorus and potassium contents after the returning of straw biochar and the burning increased in different degrees; compared with burning treatment, the nitrogen content of straw biochar treatments significantly increased by 5.79% and 30.06% by rice and rapeseed straw; compared with straw biochar, the phosphorus and potassium contents of straw burning significantly increased; the loss rate of nitrogen and phosphorus were decreased by straw biochar. The crop yields and the physical and chemical properties of soil are increased under the straw biochar returning in different rotation systems, the straw returning in the paddy- upland rotation field is superior to that in the dry farming area.