Abstract: 【Objective】 We study on the changes of nutrients, metabolites and protective enzyme contents of cotton leaves in different density and different damage time byBemisia tabacistress to cotton plant lets to reveal the interaction between whitefly and cotton. 【Method】 UsingB. tabaci, in the artificial climate room, used cotton (NJ-135) to breeding and experiments. By setting up treatment groups with different density :0 (control), 50 and 500 head/plant, covered with 140 mesh nylon mesh. After putting different density ofB. tabaci that had been fed on 24, 48 and 72h to determine the pro di aldehyde, pro line, catal ase, soluble protein content, soluble sugar and chlorophyll in the cotton leaves. 【Results】 In the groups of 50 and 500 head/plant treatment, there was a positive correlation between changes in content of total protein, proline and catalase contents in cotton leaves and the duration of feeding byB. tabaci (3.23, 4.87 and 5.55 μg/mL, 3.84, 5.38 and 5.92 μg/mL; 0.85, 0.92 and 0.99 μg/g, 0.89, 0.98 and 1.21 μg/g; 9.81, 10.98 and 18.45 U/mg prot; 12.42, 15.29 and 19.16 U/mg prot). Soluble sugar content in leaves gradually decreases with increasing feeding time (16.77, 15.83 and 15.64 mg/g; 18.10, 15.75 and 7.84 mg/g). The content levels of malondialdehyde in leaves gradually decreased and then increased with feeding stress (3.76, 3.26 and 4.44 nmol/mg prot; 4.45, 3.94 and 5.15 nmol/mg prot). The dynamics of chlorophyll content changes between low and high density treatments was different, 50 heads/plant, showing a decrease followed by an increase (1.27, 0.90 and 1.92 mg/g), and 500 heads/plant as a gradual increase (0.50, 0.86 and 1.98 mg/g). 【Conclusion】 This suggests that the activities of the defense related enzymes, nutrients, and metabolites were influenced by damage fromB. tabaci. The stress response of cotton leaves ofB. tabaci was led to the contents of related nutrients, products and defense enzymes will change. The high density ofB. tabaci was enhanced with this response, as well as the response of the time increases.