Xinluzao 64， the main local cotton variety was used to study the application effect of nitrogen reduction technology and slow-release nitrogen fertilizer on cotton under drip irrigation in Xinjiang.Three treatments including no nitrogen fertilizer （H1）， traditional full urea application （H2，300 kg/hm²）， and 20% slow-release nitrogen fertilizer with urea application （H3，240 kg/hm²） were set up.The physical and chemical properties， enzyme activity and content of inorganic nitrogen in cotton field soil were measured at different stages of cotton growth.The content of nitrogen in cotton was measured at the stage of cotton boll opening.The effects of nitrogen reduction combined with slow-release nitrogen fertilizer on nitrogen use efficiency of cotton were analyzed.The results showed that the stability of soil aggregates in the 0-20 cm soil layer treated with H3 was significantly higher than that treated with H2 （P<0.05） at each stage of cotton growth.There was no significant difference in total nitrogen between H3 and H2 treatments in the 0-40 cm soil layer.The enzyme activity in soil of H1 treatment was at a relatively low level throughout the whole period of cotton growth.The activity of urease in soil of H2 treatment was significantly higher than that of H3 treatment， while the activity of hydrogen oxide enzyme was lower than that in H3 treatment.There was no significant difference in the activity of sucrase and alkaline phosphatase between the H3 and H2 treatments.The H3 treatment reduced the leaching loss of nitrogen at the later stage of cotton growth compared to the H2 treatment.The content of ammonium and nitrate nitrogen in the soil layer of 40~60 cm in H3 treatment decreased.The nitrogen fertilizer utilization efficiency of H3 treatment was higher than that of H2 treatment （P<0.05）， reaching 45.75%， which was 7.87 percentage points higher than that of H2 treatment.The yield of cotton lint under H3 treatment increased by 18.26% compared to H1 treatment， and there was no significant difference in boll quality， yield of seed cotton and cotton lint compared to H2 treatment， which can achieve nitrogen reduction without yield reduction.It is indicated that H2 treatment enhances the stability of surface soil aggregates， maintains the high content of inorganic nitrogen throughout the whole growth period of cotton， reduces the leaching loss of nitrogen， and is beneficial for improving the nitrogen fertilizer utilization efficiency and yield of cotton.It can be popularized in cotton fields under drip irrigation.