Abstract: Through arid inland area of Xinjiang cotton brown desert soil drip irrigation test, study on conventional N (24kg/666.7m2), optimization N (16kg/666.7 m2) conditions, the proportion of fat and production of cotton used to fertilizer fertilization proportion and scale of three kinds of N way the yield and quality of cotton and photosynthetic trait. Results show that: the conventional N ratio can be recommended by the true lint yield about 205.24 kg / 666.7 m2, Conventional N and optimization of cotton fiber length of N, fiber strength, fiber spinnability differences can achieve significant influence coefficient of cotton fiber, uniformity, the difference was not significant influence elongation, The conventional N ratio can be recommended to cotton net photosynthetic rate boll period in 20μmolCO2/m2?s, and can obtain high, Conventional N and optimization N conditions, the proportion of cotton N recommendations SPAD chlorophyll optimal value.