In this paper, high performance of anisotropic de-upset nanoscale Nd-Fe-B magnets is obtained: intrinsic coercivity Hcj=1 157 kA/m, remanence Br=1.465 T and maximum energy product (BH)max=426 kJ/m³. The fabrication procedure dependence, deformation mechanism and magnetic domains of these materials are discussed. It is found that the strain activation energy of the die-upset Nd-Fe-B magnets is about 380 kJ/mol based on the Arrhenius Model. The interaction domains are the typical characteristics of the magnetic structures of the magnets. And these domains play an important role in the coercivity mechanism and the corresponding maximum application temperature for the die-upset Nd-Fe-B magnets.