PrCo5 magnet can have excellent magnetic properties and good thermal stability. In this paper, anisotropic nanograin PrCo5 hot deformed magnets with and without PrCu eutectic alloy were prepared by the spark plasma sintering technique. For the 70% hot deformed magnet with 6 wt.% PrCu, the coercivity of the magnet achieves 10.1 kOe, and is increased to be 14.6 kOe after annealed at 550°C, more than twice that of the undoped magnet (6.7 kOe). The nonmagnetic PrCu phase is mainly distributed in the interface of the grains, introducing a demagnetization coupling effect among the hard magnetic grains, resulting in large enhancement of the coercivity.