A newly developed rotational coating process has been used to coat Nd-Fe-B flake-shape powders with Zn. A uniform layer of Zn as thin as 1.5 μm can be coated on the Nd-Fe-B powders under a proper rotational coating condition. The coercivity decreases by about 4.23% and magnetization decrease by only 1.64% after Zn coating. The antioxidation, on the other hand, is greatly improved. The large mass increase during oxidation starts at 400 °C for the Zn-coated powders, 150 °C higher than that of the uncoated powders. In addition, during the high-temperature oxidation experiment from 30 °C to 450 °C, the mass of uncoated powders increases by 2.82%, while the mass of Zn-coated powders only increases by 0.40%. These results prove that the rotational coating is a very effective way to enhance the oxidation resistance of Nd-Fe-B powders, owing to the high-quality coating layer and its good isolation ability for the matrix. The process is also low-cost and easy to achieve mass production, making it a promising technique for producing high-performance Nd-Fe-B powders.