In this study, the W-25wt%Re alloys modified with 5 wt% nano-WC were fabricated by hot-pressing sintering. The influence of sintering temperature (1800 °C, 2000 °C and 2200 °C) on the phase composition, microstructure, microhardness, and tribological properties was systematically investigated. The results indicated that all the alloys consisted of W and W 2C phases, with the initial WC particles fully transforming into W 2C via carbon diffusion during sintering. As the sintering temperature increased, significant grain growth occurred: the average grain sizes of the samples sintered at 1800 °C (S18), 2000 °C (S20), and 2200 °C (S22) were 5.62 ± 3.10 μm, 7.09 ± 5.40 μm, and 16.23 ± 9.63 μm, respectively. Benefiting from the combined effects of fine-grain strengthening and dispersion of fine W 2C phases, the S18 sample exhibited the best overall performance, including a microhardness of 610 ± 11 HV 1.0. The wear scar on the S18 sample was the shallowest. The dominant wear mechanism was adhesive wear, accompanied by abrasive and oxidative wear.