Sintered　Nd-Fe-B　rare　earth　permanent　magnets　have　excellent　magnetic　properties.　But　its　Curie　temperature　is　low,　which　makes　it　limited　in　the　field　of　high　temperature　applications.　With　the　rapid　development　of　new　energy　vehicles,　wind　power　and　other　emerging　industries,　the　market　demand　for　high　temperature　sintered　Nd-Fe-B　magnets　have　been　greatly　raised.　Therefore,　in　order　to　improve　the　service　temperature　of　Nd-Fe-B　material,　new　technologies　have　been　developed　to　increase　the　coercivity　of　sintered　Nd-Fe-B　magnets.　At　the　same　time,　the　investigation　on　the　high　coercivity　sintered　Nd-Fe-B　magnets　with　low　Dy　content　or　without　Dy　content　become　the　highlights　in　order　toreduce　the　product　cost　and　consumption　of　heavy　rare　earth　metals.　It　is　found　that　the　coercivity　of　Nd-Fe-B　magnets　can　be　improved　to　a　certain　extent　by　refined　grain　technology,　grain　boundary　diffusion　technology　and　grain　boundary　doping　technology.　In　this　paper,　the　latest　research　progress　of　these　three　new　technologies　are　reviewed.　©　2017,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.