Amorphous Mg-Ni-Nd alloys were prepared by melt-spun technique and their discharge capacity was measured. Microstructure of amorphous ribbons after different charge-discharge cycles was observed using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and selected area electron diffraction (SAED). The structure evolution of amorphous (Mg60Ni25)(90) Nd-10 alloy during the charge-discharge cycles was investigated in detail. Experimental results showed that the structure evolution of amorphous ribbon was responsible for the decay of discharge capacity. During the charge-discharge cycles of amorphous (Mg60Ni25)(90)Nd-10 alloy, NdMg2Ni9 phase appeared after four cycles and Mg2Ni phase appeared after six cycles. After 20 cycles the stable phases Mg2Ni, alpha-Mg and Nd2H5 were present and the former NdMg2Ni9 phase disappeared. With crystallization of amorphous ribbon, the discharge capacity of amorphous (Mg60Ni25)(90)Nd-10 alloy dropped off. After 10 cycles the curve of discharge capacity tended to be smooth. (c) 2008 Published by Elsevier B.V.