The　fast　response　and　high　power　density　for　all-speed　of　auxiliary　braking　system　are　required　for　tracked　vehicle,　but　the　existing　hydrodynamic　retarder　can　hardly　meet　the　demand.　An　eddy　current-hydrodynamic　hybrid　retarder　(EHR)　is　presented　based　on　the　complementary　characteristics　of　eddy　current　and　hydrodynamic　retarter.　The　speed　characteristic　of　EHR　is　predicted　through　numerical　simulation.　The　best　braking　characteristics　were　obtained　by　developing　the　control　strategy　of　EHR.　The　result　shows　that　EHR　can　respond　within　0.2　s,　depending　on　the　eddy　current　brake.　It　mainly　relies　on　the　eddy　current　brake　at　the　rotating　speed　of　less　than　600　rpm,　and　depends　on　its　eddy　current　and　hydrodynamic　braking　performance　at　the　other　rotating　speeds.　HER　may　provide　280　kW　braking　power　at　1　000　rpm.　©　2018,　Editorial　Board　of　Acta　Armamentarii.　All　right　reserved.