The amorphous Mg2Ni0.95Sn0.05 + x wt% Ni(x=25,50,75,100,125)composites were synthesized by mechanical ball-milled.The microstructure and electrochemical properties of the composites were investigated.The microstructure analysis indicates that it is difficult to form amorphous structure when the Mg2Ni0.95Sn0.05 alloy is ball-milled without addition of Ni powder.The addition of Ni does favor the formation of amorphous structure.The electrochemical analysis indicates that the discharge capacity of as-cast Mg2Ni0.95Sn0.05 alloy is only 16 mAh/g and almost has no changes after 100 h ball milling.When the alloy with addition of Ni powder was milled its discharge capacity was greatly increased.With increasing of Ni content x,the discharge capacity increased first and then decreased,and reached the maximum of 625.6 mAh/g at x=75.For x=50 composite,the discharge capacity increased after increasing of the ball-milling time,and the maximal discharge capacity increased to 670 mAh/g at t=200 h.