Abstract: The changes of membrane fatty acid composition and membrane protective system of G. acuminata leaves as the temperature decreases were investigated. The results showed an increase of the unsaturation of membrane fatty acid, and an increase of the SOD activity as well as Vc content, and new isozymes of POX appeared. These strengthened the protective system’s ability to sweep away the free radical. The results suggest that changes of unsaturation of membrane fatty acid are closely related with protective system , and are adapted to the chilling resistance development in G. acuminata.