The　microstructure　evolution,　microhardness　and　wear　resistance　of　Ni45　composite　coatings　reinforced　by　insitu　NbC　were　investigated　by　means　of　scanning　electron　microscopy　(SEM),　X-ray　diffraction　(XRD),　electron　probe　microprobe　analyzer　(EPMA),　transmission　electron　microscopy　(TEM),　digital　microhardness　tester　and　wear　test　machine.　The　results　showed　that　the　matrix　was　mainly　composed　of　gamma-Ni(Fe)　solid　solution,　and　the　reinforcement　phases　consisted　of　Cr23C6　,　NbC,　Cr7　C3　,　Cr2B　and　little　content　of　Cr3C2　.　In-situ　NbC　particles　were　homogeneous　and　heterogeneous　nucleation　from　the　Nb　and　C　atoms　dissolved　in　the　molten　pool,　which　was　first　precipitated　from　the　Ni45　alloy　liquid.　With　the　increase　of　NbC　designed　content,　the　microhardness　of　coating　increased　gradually.　When　the　designed　content　was　20%,　in-situ　NbC　particles　were　regular　and　distributed　homogeneously,　and　the　composite　coating　exhibited　excellent　wear　resistance　which　was　higher　4.43　times　than　that　of　the　original　coating.