Abstract: Salinity is the major environmental factor that limits cotton germination and growth in cotton seedling period.To evaluate the potential of coronatine (COR)for alleviating salt stress on osmotic regulation and hormone of cotton seedling,hydroponical culture experiments were carried out using transgenic insect-resistant cotton( Gossypium hirsutum L.,cv.CCRI 41,CCRI 45 and 99B)treated with NaCl and COR.The results showed that coronatine increased the proline content by 110% under salinity stress,compared to NaCl treatment.Abscisic acid (ABA)content in leaves were increased by 27%,119% and 239%,respectively,under 0.01,0.1 and 1 μmol/L COR treatment,and ABA content in root were increased by 222% and 130%,respectively,under 0.1 and 1 μmol/L COR treatment.Coronatine also caused a considerable increase in jasmonate (JAs),and indole-3-acetic acid (IAA)content,which may induced the expression of genes response to salt stress,maintained the stability of membrane,thus,enhanced the ability of osmotic regulation of cotton seedlings.