The　polycrystalline　Ni-Mo-La　composite　coating　was　obtained　by　electrodeposition　through　the　addition　of　La3+　ions　into　Ni,　Mo　ions　main　salt　weak　alkaline　solution.　The　obtained　composite　contain　0.92　at.%　La.　According　to　the　law　of　ionic　activity,　the　redox　reaction　of　three　kinds　of　metal　atoms　was　studied　by　polarography　and　cyclic　voltammetry.　It　was　found　that　the　addition　of　lanthanum　ions　changed　the　composite　structural,　phase,　and　element,　and　the　OH-　ions　were　deduced　during　the　electrodeposition　in　alkaline　solution.　The　introduction　of　lanthanum　and　molybdenum　ions　negatively　shifted　the　reduction　potential　of　nickel　ions　and　broadened　the　peaks　significantly　in　the　deposition　process,　retarding　the　reduction　and　deposition　rate　of　Ni　ions,　which　was　characterized　by　a　multi-step　reduction　process　of　Mo　and　La　metal　atoms.　©　2018　by　the　authors.