In the paper, it is introduced the La_0.75Ce_0.25 (NiCoMnAl) _x (x = 4.95, 5.05, 5.15, 5.25) series of alloys were prepared with the induction melting method. The XRD test was carried out for the series of alloys and their phase structure was analyzed; their electrochemical performances were tested with the dual electrodes method and the PCT hydrogenation and dehydrogenation test was carried out. The results showed that all the four samples were with LaNi₅ phase of CaCu₅ structure, their phase composition was not changed by adjusting the stoichiometric ratio; their maximum hydrogen storage capacity decreased with the increase of stoichiometric ratio, their plateau pressure decreased first and then increased; with the gradual increase of stoichiometric ratio, their discharge capacity decreased gradually; the high-rate performance increased first and then decreased, their maximum 3C HRD value reached 89.6% when the stoichiometric ratio was 5.05; their cycling stability was enhanced with the increase of stoichiometric ratio.