To　solve　theproblems　of　an　insufficient　braking　moment　for　the　eddy　current　retarder　at　high　speed,　a　small　braking　moment　and　slow　response　of　the　hydraulic　retarder　at　low　speed,　and　a　low　power　density　of　the　existing　electromagnetic　hydraulic　retarder(EHR),　a　novel　radially　distributed　electromagnetic-hydraulic　retarder(R-EHR)　was　proposed.　The　R-EHR　fully　absorbs　the　advantages　of　the　braking　characteristics　of　hydraulic　retarders　and　eddy　current　retarders.　The　cooling　fluid　is　used　to　realize　the　braking　of　the　hydraulic　part.　At　the　same　time,　it　acts　on　the　heating　surfaces　to　improve　the　torque　of　the　electromagnetic　part.　In　this　paper,　finite　element　models　of　the　flow　field　and　electromagnetic　field　are　established　to　predict　braking　performance.　The　braking　performance　of　the　R-EHR　is　obtained　by　bench　test,　the　error　between　the　simulation　and　experimental　data　is　compared,　and　the　experimental　data　are　analyzed.　The　results　show　that　the　proportion　of　electromagnetic　braking　torque　in　the　novel　R-EHR　is　more　reasonable.　The　braking　torque　increased　by　26%　and　the　power　density　increased　by　37.5%　at　2000　RPM　compared　to　that　of　the　EHR.　The　R-EHR　can　control　the　braking　torque　only　by　adjusting　the　current,　thus　simplifying　the　control　system.