In this study,the effects of mild(900 mL),moderate(400 mL),severe(300 mL) and CK(1 200 mL) drought stress and rewatering on CBF₁ transgenic cotton (24C-1) and wild type (TH₁) by different sites of leaf photosynthetic parameter and chlorophyll content changes of vitro leaf in dark conditions,and field experiment at seedling stage,bud stage,flowering stage,the bell stage with water stress treatments on production.The results showed that:(1)From the drought stress with different times to re-water 3 d,the net photosynthetic rate(P_n) and maximal photochemical efficiency(F_v/F_m) showed a trend of increasing firstly,decreasing then.Leaf retain number were significantly higher than that of wild type plant,at the top of the leaves is greatly damage to compare middle leaves under drought stress;with the stress time extended that Chl a,Chl b contents decreased,the decreased rate were significantly higher than that of wild type plant.(2)For the date of field experiment compared with normal irrigation treatment water stress at the seedling stage,bud stage,flower stage,bell stage the lint yield,seed index,seed quality,plant height of cotton decreased significantly,transgenic and wild type of the seed cotton yield reduced by 78.4%,55.1%,12.7%,8.3% and 80.4%,55.4%,19.2%,14.4%,respectively.The cotton yields of different stages have been affected by the water stress.But transgenic cotton yields are still significantly higher than that of wild type.These results demonstrated that the CBF₁ gene expression enhanced the growth and development of the transgenic cotton plant,and indicated that the CBF₁ transgenic cotton could improve the drought resistance.