Aiming　at　the　complex　manufacturing　processes　of　the　traditional　hydraulic　retarder　structures　such　as　axial　inclined　blade,　closed　torus,　inlet　and　outlet　channel,　a　new　retarder　structure　with　vertical　blade　and　dual　torus　was　proposed,　which　greatly　simplified　the　manufacturing　processes.　By　establishing　the　mathematical　model　and　using　computational　fluid　dynamics　technology,　the　change　rules　of　retarder　braking　torques　were　obtained　and　verified　by　bench　test.　The　results　show　that:　the　change　rules　of　the　braking　torques　of　the　novel　retarders　are　basically　the　same　as　that　of　the　traditional　retarders,　the　braking　torques　of　the　novel　retarders　reach　1　490　N•m　at　1　750　r/min,　and　the　change　rules　are　similar　to　the　calculation.　The　relative　errors　are　less　than　12%,　which　confirmes　the　reliability　of　the　calculation.　In　conclusion,　the　braking　performance　of　this　retarder　basically　satisfies　with　the　vehicle　requirements　for　braking　torque　and　braking　stability.　©　2020,　China　Mechanical　Engineering　Magazine　Office.　All　right　reserved.