Abstract: NdFeB ultrafine particles were prepared by hydrogen-dismutation-dehydrogenation-recombination method by using NaCl solid particles and surfactant assisted high-energy ball grinding. The effects of oleic acid content, milling time and NaCl on crystal structure, magnetic properties and microstructure of NdFeB were investigated. The results showed that appropriate oleic acid addition could help to form nano-scale flake particles after high-energy ball milling, and had good c-axis orientation. After the addition of NaCl, the particle size and thickness of the powder were 0.24 μm and 13.98 nm after ball milling for 6 h with 30% oleic acid content, coercivity H_c=2.48 kOe and high orientation M_r/M_s=0.841. The results show that NaCl synergies indicate that high energy ball milling of active agents can help to prepare ultrafine NdFeB particles with ultra-thin thickness and high orientation.