The mung bean variety Bailü No.9 was used in this experiment. Bailü No.9 was soaked and sprayed withCu SO4（50 mmol/L）, Mg SO4（50 mmol/L） and Fe SO4（50 mmol/L）, with distilled water as control. The effect of Cu²⁺,Mg²⁺, Fe²⁺in branching stage,flowering period and maturation period on Chlorophyll,SOD, POD, MDA of mung beanwas explored. The results showed that chlorophyll, MDA, activity of SOD and POD increased by Cu²⁺, Mg²⁺, Fe²⁺treatment in above three periods. Soaking was the best among the three treatments. The effects of Mg²⁺, Fe²⁺were bet-ter than Cu²⁺.