The　phenol　formaldehyde　(PF),　a　kind　of　heat-resistant　binder,　was　used　to　prepare　bonded　Nd-Fe-B　magnets　via　mold　pressing.　The　magnetic　properties,　compressive　strength,　and　microstructure　of　the　magnets　were　systematically　investigated.　The　magnetic　measurements　show　that　PF　binder　endows　Nd-Fe-B　magnets　excellent　magnetic　properties.　Moreover,　the　magnets　can　keep　the　original　shape　and　exhibit　usable　magnetic　properties　at　200　degrees　C.　With　increasing　binder　content,　the　compressive　strength　of　the　magnets　reach　253.6　MPa　with　4　wt.%　PF　binder,　which　is　14　times　higher　than　that　of　epoxy　resin　bonded　Nd-Fe-B　magnets.　In　addition,　the　reason　of　high　compressive　strength　was　investigated.　The　main　chain　of　PF　binder　molecule　contains　rigid　structure　like　benzene　rings,　which　can　form　hard　cross-linking　network　structure　in　the　gaps　of　magnetic　powders　making　the　bonded　magnets　with　high　strength.　Further　fracture　surface　morphology　observation　and　energy　dispersive　X-ray　analysis　reveal　that　liquid　PF　binder　can　permeate　into　gaps　between　the　magnetic　powders　during　the　process　of　warm-molding　and　exert　excellent　bonding　effect.　Two　mechanisms　of　action　can　endow　PF/Nd-Fe-B　magnets　excellent　mechanical　strength　and　heat　resistance.