The self-discharge property of La0.65Mg0.35Nix (x=3.0~3.5) hydrogen storage alloy electrodes was studied systematically. The results show that with the Ni content increasing, the maximum discharge capacity of the alloy electrodes increases from 350.6 mAh·g-1 (x=3.0) to 351.2 mAh·g-1 (x=3.1) and then decreases to 244.1 mAh·g-1 (x=3.5). Moreover, the capacity retention rate of 72 h self-discharge increases from 77.7% (x=3.0) to 79.5% (x=3.1), and then decreases to 63.5% (x=3.5), which indicates that the self-discharge property of the alloy electrodes is improved by the appropriate Ni content. The variety of the self-discharge property of the alloy electrodes with x value was analyzed by testing the electrochemical pressure-component-temperature (P-C-T) curves and corrosion curves of the alloy electrodes.