The　nanocrystalline　Ni-Mo　coating　was　obtained　in　the　basic　nickel　carbonate　solution.　The　coating　surface　and　structure　were　analyzed　by　using　scanning　electron　microscopy　(SEM),　X-ray　diffraction　(XRD).　The　results　show　that　the　coating　is　composed　of　two　phases　of　NiMo　and　β-Ni4Mo,　and　its　grain　size　is　about　23.2nm.　NiMo　and　β-Ni4Mo　solid　solution　exhibits　preferred　orientation　(111)　and　(200),　respectively.　The　electrodepositing　parameters　have　great　influence　on　surface　morphology　and　binding　strength　of　the　coatings.　The　better　electrodeposited　Ni-Mo　alloy　coating　is　obtained　when　the　solution　pH　value　is　around　10.0,　the　temperature　is　30~35°C,　and　the　current　density　is　2~5A/dm2.　With　increasing　the　molybdenate　concentration　in　the　bath,　Mo　content　of　the　coating　increases　and　hardness　of　the　coating　first　increases　to　a　peak　value　at　about　8~12g/L,　and　then　decreases.　The　increase　of　coating　hardness　is　due　to　the　solid　solution　strengthening.　Molybdate　and　ammonia　concentration　in　the　bath　influence　the　internal　stress　of　the　coating.