T₃ generation of KatE transgenic upland cotton was applied to investigate the drought resistance of transgenic cotton.Transgenic cotton were detected and identified by kanamycin and PCR.These positive plants were used to the drought resistance experiment with control plants,with the aim to compare the differences of physiological and biochemical,identify drought resistance between transgenic plants and control plants under drought stress until the cotton harvest.The results show that:(1)With drought stress to squaring stage,the drought resistance physiological indexes were not significantlt different between transgenic and contrast plants.(2)Water stress to budding peak stage and full-bloom stage,transgenic cotton leaf relative water content,F_v/F_m,CAT activity,leaf net photosynthetic rate(P_n),stomatal conductance(G_s) and transpiration rate(T_r) were significantly or extremely significantly higher than that of controlled plant.Drought stress to boll opening period,the transgenic cotton plant height,branch number and boll number were significantly or extremely significantly higher than that of controlled plant,transgenic and contrast of the cotton seed cotton yield than the normal irrigation treatment reduced by 57.5% and 60.1%,respectively.The whole growth period of cotton production has been affected by the water stress,but transgenic cotton seed and cotton yield is still significantly higher than that of control.The experimental results show that KatE cotton showed good physiological and growth advantage under the natural rainfull condition(water stress) in Xinjiang Shihezi,which help to increase drought resistance of the cotton.