Abstract: Cu–Nb microcomposite wire was successfully prepared by a groove rolling process. The effects of groove rolling on the diffraction peaks, microstructure, and properties of the Cu–Nb microcomposite were investigated and the microstructure evolutions and strengthening mechanism were discussed. The tensile strength of the Cu–Nb microcomposite wire with a diameter of 2.02 mm was greater than 1 GPa, and its conductivity reached 68% of the International Annealed Copper Standard, demonstrating the Cu–Nb microcomposite wire with high tensile strength and high conductivity after groove rolling. The results show that an appropriate groove rolling method can improve the performance of the Cu–Nb microcomposite wire.