Abstract: ：The storage life of ultra-dried C. arborescens seed （MC 2.8%-4.2% ） is significantly prolonged under outdoor temperature condition. After 25-month＇s storage at outdoor temperature ,the contents of MDA and relative conductivity in ultradried seed are lower than those of the non ultra-dried （MC〉5%）one. The seed vigor, activities of dehydrogenase and peroxidase of ultra-dried seed are much higher than those of the non ultra-dried one. The results show that ultra-drying of C. arborescens seed could preserve its vigorous vitality. Low extent of lipid peroxidation proves to be one of the physiological causes of storage- tolerance in ultra-dried C. arborescens seed.