Pot experiments were used to study the effect of EDTA on zinc accumulation,photosynthetic pigment content and chlorophyll fluorescence under zinc stress in different alfalfa(Medicage sativa L.)leaves of three cultivars Medicago sativa ssp.,Vitoria Alfalfa,Medicago sativa cv..In order to explore effective avenue to improve alfalfa(Medicage sativa L.)resistant ability under zinc stress.The results of the study indicated that:(1)zinc contents in three cultivar leaves were significantly higher than that in control group.Compared with zinc stress alone,the addition of EDTA strikingly enhanced zinc absorption in leaves.(2)In comparison with different cultivars,photosynthetic pigment content of Medicago sativa ssp.was higher than that in control group.After EDTA treatment,contents of chlorophyll a,chlorophyll b,total chlorophyll and carotenoids in Medicago sativa ssp.leaves were remarkably higher than that in two other cultivars.(3)The treatment of EDTA increased Fo,Fv,Fm and Fv/Fm levels in Medicago sativa ssp..Our research indicates that EDTA can promote the accumulation of photosynthetic pigment,reduce the dissipation of excessive excitation energy,improve the transmission efficiency of photosynthetic electron,and minimize the damages to alfalfa leaves PSII caused by zinc stress effectively,all of which coherently boost resistance capability to zinc in Medicago sativa ssp.cultivar.As can be seen,EDTA with the appropriate concentration of 10μg could coefficient alleviate the damage of Zn stress to Big leaf,reduce dissipation of excess excitation and improve photochemical electron transport efficiency and efficiently protect from PSII damage,EDTA obviously promoted the Zn resistance of Medicago sativa ssp.under Zn stress.