In order to study the effects of different nitrogen fertilizer management on soil nitrogen and cotton nitrogen uptake and utilization in cotton fields under the condition of straw return，and to provide a theoretical reference for the nitrogen fertilizer management in cotton under the condition of straw return，a split-zone design was adopted in 2023，with straw not returned to the field(T0)and straw returned to the field(T1)as the main zones，and five types of nitrogen fertilizer management as the subzone.The five types of nitrogen fertilizer management included no nitrogen fertilizer(F0)，conventional fertilizer(F1:application of ordinary compound fertilizer，urea applied during the bolling period with base and chase ratio being 6∶4)，nitrogen reduction treatment 1(F2:20% nitrogen reduction compared with F1 base fertilizer and chase fertilizer)，and controlled-release urea(F3:resin-coated urea，with a 90-day controlled-release period)，nitrogen reduction treatment 2(F4:20% nitrogen reduction compared to F3).The effects of straw returning to the field and nitrogen fertilizer management on cotton soil nitrogen transformation，cotton soil nitrogen pool and its management index，cotton yield and nitrogen uptake and utilization of cotton plants were analyzed.The results showed that straw return and controlled-release urea application increased the soil transformation rate at seedling and bolling stages，the total nitrogen content，total soluble nitrogen，ammonium nitrogen and nitrate nitrogen of soil at the flocculating stage，and also increased the nitrogen uptake of cotton at all stages of the cotton crop，thereby increasing the cotton yield.At the level of 180 kg·hm-2，the reduction of nitrogen caused a decrease in soil transformation rate，a decrease in total nitrogen content ，total soluble nitrogen，ammonium nitrogen and nitrate nitrogen in the flocculent stage，and a decrease in nitrogen uptake of cotton in all periods，which ultimately led to a reduction in yield.The application of controlled-release urea in combination with straw return could accelerate soil nutrient transformation，increase soil available nutrient content，improve cotton nitrogen uptake，enhance fertilizer utilization efficiency，and then improve yield.