NiCr-Cr₃C₂-based coatings are widely employed in extreme environments due to their excellent high-temperature resistance. However, their tribological mechanisms and microstructural evolution above 600 °C remain unclear. In this study, the (NiCr-Cr₃C₂)/NiCr composite coating was prepared using HVOF technology. The tribological behavior of the composite coating within the temperature range of 600–1000 °C was comprehensively investigated through microstructural analysis (SEM, EDS, XRD, and XPS) and mechanical property evaluation (hardness and toughness). The results show that the wear rate reached a minimum at 700 °C due to a sub-micron NiCr network and dispersed carbides, while the friction coefficient was lowest at 900 °C under oxidative wear dominated by Cr₂O₃/NiO/NiCr₂O₄. Below 800 °C, abrasive/oxidative wear with Cr₂O₃/Ni₂O₃ products prevailed; when the temperature exceeded 900 °C, the secondary carbides within the coating tended to aggregate and grow, shifting the dominant wear mechanisms to oxidative and adhesive wear. These findings elucidate the friction-oxidation coupling mechanisms and provide critical insights for high-temperature coating design.