Abstract: The effects of exogenous glycine betaine on the physiological responses of cotton seedings under salt stress were studied. No.18 cotton widely cultivated in Xinjiang was selected as study object under 200 mmol/L NaCL stress and spraying 5 mmol/L, 10 mmol/L glycine betaine respectively. The changes of physiological index were measured after 7 day. The results showed that under the condition of no salt stress, the content of proline and soluble sugar were improved significantly, while malonaldehyde (MDA) and antioxidative enzyme were not affected by spraying glycine betaine.The content of MDA increased significantly and proline, soluble sugar and antioxidative enzymes activity increased under salt stress. After spraying glycine betaine under salt stress, the production of MDA were inhibitted effectually, at the same time the content of proline, soluble sugar and antioxidative enzyme increased further more. Glycine betaine alleviated the damage of cotton seedings caused by salt tress, and 5 mmol/L glycine betaine had better effect.