This　paper　presents　a　CFD-based　numerical　simulation　method　to　evaluate　the　braking　performance　of　hydraulic　retarder.　This　method　is　based　on　the　theory　of　fluid　transmission　and　the　principle　of　computational　simulation.　The　braking　performance　of　hydraulic　retarder　has　been　simulated　and　calculated　at　the　aspect　of　construction　and　so　on.　The　advantage,　disadvantage　and　applicability　of　the　CFD　numerical　simulation　method　have　been　analyzed.　The　calculated　result　has　been　compared　with　the　experiment　results　of　simulation　experiment　table.　The　conclusion　is　that　the　CFD-based　numerical　simulation　method　is　quite　precise　to　evaluate　the　braking　performance　of　hydraulic　retarder.　It　presents　a　new　method　for　research　in　the　braking　moment　performance　of　a　hydraulic　retarder.