Electrochemical　impedance　spectroscopy　(EIS)　tests　of　anisotropic　Nd-Fe-B　magnets　prepared　by　spark　plasma　sintering　(SPS)　technique　were　carried　out　to　investigate　their　corrosion　kinetics　in　different　solutions.　According　to　the　Nyquist　and　Bode　diagrams,　convenient　equivalent　circuit　was　modeled　and　the　values　of　the　proposed　equivalent　circuit　components　were　calculated.　It　was　found　from　the　EIS　plot　formats　that　the　electrochemical　reaction　of　SPS　Nd-Fe-B　magnets　was　controlled　by　the　step　of　surface　charge　transfer　i.e.　activation　polarization　in　alkaline　solution,　while　controlled　by　step　of　active　substances　adsorption　on　the　magnet　surface　in　salt　and　acidic　solutions.　Compared　with　conventional　sintered　Nd-Fe-B　magnets,　the　SPS　Nd-Fe-B　magnets　possess　better　chemical　stability　in　saline　and　weak　acidic　environment.　©　2005　Trans　Tech　Publications,　Switzerland.