This　study　aims　to　design　a　magnetorheological　(MR)　brake　with　self-protection　and　heat　dissipation　functions　for　elevators.　Using　permanent　magnet　system　technology,　the　MR　brake　can　not　only　form　a　double　magnetic　field　with　excitation　coils　to　improve　braking　torque　under　normal　operation　but　also　provide　braking　torque　for　protection　in　case　of　power　failure.　In　addition,　a　cooling　channel　is　designed　in　the　braking　shaft　of　the　MR　brake　to　ensure　effective　heat　dissipation　of　the　MR　fluid.　In　this　work,　the　structure,　material,　and　magnetic　circuit　of　the　MR　brake　is　first　developed.　Then,　finite　element,　magnetic　field,　and　thermal　field　analyses　are　conducted　on　the　brake.　Finally,　a　prototype　of　the　brake　is　produced,　and　its　performance　is　tested.　Results　show　that　the　braking　torque,　especially　the　self-protection　function,　meets　the　demands　of　the　elevator;　the　increase　in　temperature　during　braking　is　minor;　and　the　noise　level　is　low.