Ti0.10Zr0.15V0.35Cr0.10Ni0.30 + 1% La0.85Mg0.25Ni4.5Co0.35Al0.15 (mass fraction) composite hydrogen storage alloy was prepared by two-step arc melting. Results of XRD and SEM-EDS show that the main phase of the composite alloy is composed of V-based solid solution phase with bcc structure and C14 Laves phase with hexagonal structure. Electrochemical studies show that distinct synergetic effect appears during the composite process. P-C-T properties, activation performance, maximum discharge capacity, cyclic stability, low temperature dischargeability and high rate dischargeability of the composite alloy are significantly improved. Comparing with the matrix alloy, the composite alloy electrode has smaller charge-transfer resistance, higher exchange current density and bigger hydrogen diffusion coefficient, which seems to be related to formation of the secondary phase