Abstract: Cu–30Ni–5Nb alloys were prepared by vacuum hot-pressing method. The effects of hot-pressing temperature on the microstructure, relative density, melting point, and thermal conductivity of the Cu–30Ni–5Nb alloys were studied. The results show that, with the increase of the hot-pressing temperature from 800 to 950 ℃, the melting point of the Cu–30Ni–5Nb alloys firstly decreases and then increases, and the melting point is the lowest (1178.92 ℃) at 900 ℃. However, the thermal conductivity of the copper alloys increases firstly and then decreases with the increase of the hot-pressing temperature from 800 to 950 ℃, and the thermal conductivity is the highest (30.65 W·m⁻¹·K⁻¹) at 900 ℃. When the hot-pressing temperature is 875 ℃, the Cu–30Ni–5Nb alloys show the good comprehensive properties with the relative density of 98.66 %, the melting point of 1180.86 ℃, the thermal conductivity of 29.54 W·m⁻¹·K⁻¹, and the alloy yield strength of 355.74 MPa, which are more suitable for the performance requirements of the cooling water jacket.