Misch-metal　(MM)　containing　four　kinds　of　rare　earth　elements　of　La,　Ce,　Pr　and　Nd,　leads　to　the　complex　multi-main-phase　(MMP)　structure　of　MM-based　sintered　magnets.　In　order　to　prepare　high-performance　MM-based　sintered　magnets,　it　is　necessary　to　explore　the　correlation　between　the　microstructure　and　properties.　Here,　the　MMP　[(Pr,　Nd)(0.65)MM0.35]-Fe-B　sintered　magnets　were　prepared　by　the　mixtures　of　MM-free　Pr-Fe-B　powders　and　MM-containing　(Nd0.5MM0.5)-Fe-B　powders,　and　the　microstructures　of　the　magnets　were　controlled　by　tuning　annealing　conditions　to　optimize　the　magnetic　properties.　The　results　show　that　the　continuous　RE-rich　grain　boundary　(GB)　phases　are　formed　between　the　adjacent　main　phase　grains　by　annealing,　which　is　beneficial　to　weaken　the　short-range　ferromagnetic　coupling　and　improve　the　coercivity.　On　the　other　hand,　the　interdiffusion　in　the　main　phase　grains　will　take　place　during　the　annealing,　which　makes　the　composition　of　the　main　phase　grains　to　homogenize　gradually.　Thus,　the　magnetic　impedance　effect　of　the　MM-rich　grains　by　the　Pr-rich　grains　is　weakened,　leading　to　the　reduction　of　coercivity.　Combining　these　two　factors,　the　MMP　[(Pr,　Nd)(0.65)MM0.35]-Fe-B　magnet　annealed　at　420　degrees　C　possessing　optimal　microstructure　could　obtain　excellent　magnetic　properties　of　H-cj　=　11.03　kOe　and　(BH)(max)　=　38.21　MGOe.