The effects of silane coupling agent doping on the microstructure and microwave properties of melt-spun Nd-Fe-Co alloys were investigated. All as-milled powders, with or without silane coupling agent treatment, were characterized as flake-like shape. However, it is found that with the addition of 0.25 mL coupling agent, the as-milled Nd-Fe-Co powders can deagglomerate and become more uniform dispersion with smaller thickness. In contrast, the excessive addition of coupling agent led to somewhat higher thickness of the flakes and much more amount of coupling agent on the surface of powder. The electromagnetic properties show that the Reflection loss will arrive -27.1 dB at 4.2 GHz, for the addition of 0.25 mL coupling agent powders. The probably reasons for this are discussed on the basis of the morphology of the powders, uniform dispersion and the physical coating between the polymer and coupling agent. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 2344-2347, 2009