The　coercivity　mechanism　of　anisotropic　Nd2Fe14B-based　magnetic　powders　prepared　by　hydrogenationdecomposition-esorption-recombination　process　was　studied.　Polarization　and　corresponding　differential　susceptibility　curves　of　the　powders　in　its　thermally　demagnetized　state　were　measured.　Microstructure　and　constituents　of　the　powders　were　investigated　by　means　of　transmission　electron　microscope　and　scanning　electron　microscope　with　energy　dispersive　X-ray　detector.　In　addition,　theoretical　calculation　of　the　intrinsic　coercive　force　of　the　magnetic　powders　was　performed.　It　is　concluded　that　the　magnetic　hardening　mechanism　of　the　powders　is　the　pinning　of　domain　walls　at　grain　boundaries　of　the　Nd2Fe14B　main　phase　and　Nd-rich　phase　that　distributes　homogeneously　around　some　conglomerations　composed　of　fine　N2Fe14B　grains.　The　coercive　force　of　the　powders　is　mainly　determined　by　the　pinning　of　domain　walls　by　Nd-rich　boundary　phase.　(C)　2003　Elsevier　B.V.　All　rights　reserved.