Nanocrystalline　Ni-Co-Fe　alloy　coatings　with　smooth　and　bright　surface　were　synthesized　by　pulsed　electrodeposition.　The　microstructure,　chemical　composition,　thermal　stability　and　hardness　of　the　coatings　were　studied　by　XRD,　TEM,　EDS,　DSC　and　microhardness　tester,　respectively.　The　results　reveal　that　the　grain　size　of　the　nanocrystalline　Ni-Co-Fe　alloy　coatings　with　FCC　structure　decreases　with　increasing　the　content　of　Co　in　the　coatings.　The　microhardness　of　Ni-Co-Fe　alloys　increases　with　the　increase　of　the　annealing　temperature　after　annealed　at　low　temperatures,　and　reaches　the　peak　value　at　300-375　°C,　showing　a　significant　hardening　during　annealing,　and　the　hardness　decreases　with　increasing　the　annealing　temperature　further.　The　grain　grows　slowly　when　the　annealing　temperature　is　lower　than　375　°C,　while　the　rapid　grain　growth　occurs　during　annealing　above　450　°C,　showing　a　strong　(111)　texture.　The　DSC　results　obtained　at　the　heating　rate　of　20　°C/min　show　that　the　peak　temperature　value　for　the　grain　growth　in　nanocrystalline　Ni-Co-Fe　alloy　coatings　increases　with　increasing　the　content　of　Co　in　the　coatings.　The　activation　energy　obtained　from　the　Kissinger　equation　for　the　grain　growth　of　Ni-Co-Fe　alloy　coatings　increases　with　increasing　content　of　Co　in　alloy　coatings.