Abstract: Objective and MethodThe purpose of this research was to reveal the absorption law of nitrogen,phosphorus and potassium nutrient by cotton plant under different nitrogen fertilizer rate.Result and ConclusionThe results demonstrated that when there was minimum accumulation of nitrogen,phosphorus and potssium of cotton plant with different treatments in the seedling stage of cotton,it was increased in bud stage,it reached a peak in flower bolling stage,but it was decreased in boll opening state.Among all the treatments,the productive period of accumulation of nitrogen,phosphorus and potassium treated with N_2 was the longest,which reached 54-100 d,57-120 d,44-89 d,respectively after sowing,which was earlier and longer than that of other treatments.The nitrogen fertilizer rate of the highest seed cotton yield was 348.32 kg/hm~2,the economic nitrogen fertilizer rate was 320.46 kg/hm~2.