The degradation mechanism of Ti0.26Zr0.07V0.24Mn0.1Ni0.33 alloy electrode was investigated by means of FESEM-EDS, EIS and ICP-MS. The decrease of hydrogen diffusion coefficient (D), the increase of charge transfer resistances (Rct), and the dissolution of V, Ti and Zr elements to KOH solution with charge/discharge cycling should be responsible for the performances degradation of the alloy electrode.