Static　state　immersion　experiments,　polarisation　curve　and　electrochemical　impedance　spectroscopy　tests　have　been　applied　to　investigate　the　corrosion　kinetics　for　both　spark　plasma　sintered　(SPS)　and　conventional　sintered　Nd-Fe-B　magnets　in　NaCl　electrolyte.　Effect　of　microstructure　modification　on　their　chemical　stability　of　the　magnets　was　discussed.　The　electrochemical　reactions　of　both　magnets　are　controlled　by　the　step　of　active　substances　adsorption　process　at　the　open　circuit　potential　and　the　anodic　potential,　which　turn　to　diffusion　process　at　the　cathodal　potential.　Although　both　magnets　are　susceptible　to　corrosion　in　saline　electrolytes,　SPS　magnets　are　more　corrosion　resistant　than　conventional　sintered　magnets　due　to　their　special　microstructure　that　is　different　from　those　of　conventional　sintered　magnets.　In　SPS　magnets,　the　grain　size　of　the　Nd(2)Fe(14)B　main　phase　is　fine　and　uniform,　only　a　few　Nd　rich　phase　form　along　the　grain　boundaries　of　Nd(2)Fe(14)B　phase,　while　most　of　them　agglomerate　into　triple　junctions　as　small　particles.　Such　microstructure　effectively　restrains　the　aggressive　intergranular　corrosion　along　Nd　rich　phases.　As　a　result,　the　SPS　magnet　possesses　excellent　corrosion　resistance　in　NaCl　electrolyte.