The experiment was conducted to study the effects of long-term straw returning and organic fertilizer application on soil properties and cotton yield to provide basis for enhancing soil fertility and increasing cotton yield in the Yellow River Basin.A 12-year locational trial was conducted to study the effects of straw return with fermented chicken manure on soil structure，fertility and yield.Four treatments were set up in the experiment，including only chemical fertilizer N and P (NP，used as control)，N and P + straw returning (NPS)，N and P + organic fertilizer (NPM)，N and P + cotton straw returning + organic fertilizer (NPSM).The results showed that NPS，NPM and NPSM significantly reduced the soil bulk density of 0～30 cm soil layer compared with the control；significantly reduced the content of soil microagglomerates of <0.25 mm in 0～10 cm soil layer，and significantly increased the content of larger agglomerates of 0.5～1 mm；significantly increased the content of soil organic matter and alkaline nitrogen in 0～40 cm soil，among which the soil organic matter of 0～20 cm was increased by 14.2%，20.2% and 42.5% and the alkaline nitrogen of 0～20 cm soil layer was increased by 30.1%，57.4% and 207.9%，respectively；the available phosphorus and available potassium content of 0～20 cm soil layer of NPSM and NPM were significantly increased by 357.8% and 181.4%，91.5% and 34.0%，respectively；the soil pH of NPSM was significantly lower compared with that of NP treatment.NPS，NPM and NPSM lint yields were significantly increased by 11.1%，13.3% and 24.9%，respectively.The seed cotton yield of NPSM was highly significantly negatively correlated with 0～20 cm soil layer soil bulk density，but significantly positively correlated with soil aggregates and soil organic matter content，and significantly negatively correlated with pH.Based on the application of chemical fertilizers，long-term cotton straw returning with organic fertilizer application can reduce soil bulk density，improve the soil aggregate structure，enhance the supply of soil alkaline nitrogen，available phosphorus and available potassium，and increase the organic matter content and cotton yield.The effects of long-term cotton straw returning combined with organic fertilizer application on soil improvement and yield increase were better than cotton straw returning or organic fertilizer application alone，the reasonable application of seraw combined with organic manurer in cultivated land fertilization should be strengthened，and chemical fertilizer reduction and high-yield cultivation measures should be taken to improve soil quality and production efficiency.