TiB2p(-TiBw)/Cu hybrid copper matrix composites were fabricated by in situ reaction of Cu–Ti and Cu–B double-beam melts in combination with rolling. La was added on both sides of the melts and the effect of La addition on the microstructure and properties of TiB2(-TiB)/Cu hybrid composites were investigated. The results show that both the hybrid reinforcements and copper matrix are refined, and the reinforcements are more evenly distributed in the matrix with the addition of La. Meanwhile, the addition of La has no effect on the type of reinforcements. Accordingly, a good comprehensive performance of TiB2(-TiB)/Cu composites was achieved with addition of La and post-rolling treatment. Besides, the refinement mechanisms of reinforcements and copper matrix are analyzed. The reasons for the improved performance are also discussed.