In this paper, a multi-core composite wire (3 #) with graphene-coated niobium powder reinforced Cu-Nb was prepared by using powder casting technology, Cu-Nb multi-core composite wire (4#) reinforced the grapheme and niobium powder, and Cu-Nb multi-core composite wire (5#) reinforced pure niobium powder. It is found that the i ntensity of Nb (110) diffraction peak is obviously enhanced after 800 ℃ / 60h heat treatment by the optimized heat treatment process.The microstructure and energy spectrum analysis (EDS) show that the high temperature heat treatment is favorable for the slight diffusion of Cu / Nb interface between, the bonding strength of interface and wire plasticity have been significantly improved.The results show that the conductivity of Cu-Nb-C-Nb wire with graphene-coated niobium powder is better than that of the other two kinds of wires. Finally, Plastic deformation mechanism and micro-mechanism of performance change of the three different materials are analysised.The idea of further optimization of the process is put forward, which opens up a new direction for the preparation of high strength and high conductivity multi-element composite wire.