Abstract: [Objective] Jasmonic methylester transferase(JMT)can effectively facilitate the production of jasmonic methylester,so that it enhances plant drought resistance.[Method]A 450 bp silence fragment of GhJMT was cloned from cotton XLZ17(Gossypium hirsutum)using PCR amplification,and then constructed into vector pTRV.The recombinant plasmid pTRV-GhJMT was transformed into competent Agrobacterium tumefaciens(GV3101).Cotton seedlings in hydroponic conditions were infected with the transformed A.tumefaciens GV3101.After one month,the growing cotton seedlings were treated with PEG6000 for 24 h.The water content,the molality of osmotic adjustment substances,photosynthetic pigments,antioxidants and malondialdehyde(MDA)as well as enzymes activities in cotton leaves under drought stress were measured.[Result]The results showed that content of soluble sugar,ASA,betaine,proline and SOD were reduced by 42.1;,36.6;,69.4;and 71.6;compared with the pTRV-00,and MDA,O2-and H2O2 were increased 0.43,1.45 and 0.59 times compared with pTRV-GhJMT,respectively.[Conclusion]Our results demonstrate that GhJMT gene silencing can directly affect the physiological and biochemical characteristics of cotton seedlings treated with drought stress and reduce drought resistant ability of cotton.