The phase structure and electrochemical properties of La0.67Mg0.33Ni2.5Cu0.5 alloys as cast and treated by heat treatment and magnetic-heat treatment were studied in this paper. The influence of the heat treatment and magnetic-heat treatment as well as Ni substituted partly with Cu on the phase structure and electrochemical properties of La-Mg-Ni-Cu alloys were investigated by XRD and SEM analysis. The results show that the retention of discharge capacity of as-cast La0.67Mg0.33Ni2.5Cu0.5 alloy is increased to 72.44% from 64.40% after 50 cycles. The maximum discharge capacity of La0.67Mg0.33Ni2.5Cu0.5 alloy after magnetic-heat treatment is 328.2mAh/g, which is 31.51% larger than that of La0.67Mg0.33Ni2.5Cu0.5 alloy after heat treatment. Its retention of discharge capacity is 75.89% after 50 cycles. The characteristic of discharge voltage platform is much flatter and longer, the limit current density is increased and the diffusion speed of hydrogen in the alloys increases.