To systematically investigate the influence of heat treatment temperature on the cavitation erosion and sliding wear behavior of nanostructured WC–10Co–4Cr coatings—a topic that has received limited attention in prior research. The coatings were deposited on TC6 substrates via an improved high-velocity oxygen-fuel (HVOF) process and subsequently heat-treated at 500, 700, 900, and 1100 °C under argon protection. Cavitation tests were conducted in deionized water using an ultrasonic vibratory apparatus, while dry reciprocating sliding wear tests were performed to evaluate tribological performance. Results indicate that increasing the heat treatment temperature markedly improves cavitation erosion resistance. The coating treated at 1100 °C (H1100) showed a porosity of only 0.23 % and a 77.3 % reduction in mass loss relative to the as-sprayed coating, attributed to microstructural densification that suppressed crack initiation and propagation. In wear tests, heat-treated coatings exhibited lower friction coefficients, with the H900 condition achieving the lowest value (0.291) and wear rate (0.329 mm 3/N·m). The dominant wear mechanisms were identified as oxidative wear and micro-cutting. Heat treatment also enhanced the coating's toughness and load-bearing capacity, leading to reduced spalling. These findings demonstrate that post-deposition heat treatment is an effective strategy for enhancing both cavitation and wear resistance of nanostructured WC–10Co–4Cr coatings.