Carbon nanosheets (CNSs) reinforced copper composites are obtained with a molten salt route for uniform distribution of carbon in the copper matrix. The structures and properties of the composite are thoroughly characterized and tested. The mechanical properties of the composite are greatly improved compared to pure copper. The effects of annealing temperatures and carbon contents on the mechanical properties of composites are investigated and discussed. When the annealing temperature is 800 ∘ C, the composite has excellent comprehensive properties. Its yield strength is 283 MPa, which is 3.14 times that of pure copper, and its hardness is 78[Formula: see text]HV, which is 1.77 times of pure copper. The simple and low-cost preparation process opens up a novel route for the preparation of high-performance copper-based composites.