Visual　navigation　simulation　tests　are　able　to　verify　the　robustness　and　accuracy　of　navigation　algorithms　for　Unmanned　Aerial　Vehicles　(UAVs)　and　expediting　the　iterative　optimization　of　the　algorithms.　Traditional　computer　model-based　hardware-in-the-loop　simulations　fall　short　in　realizing　real　visual　navigation　flight　tests,　so　it　is　necessary　to　design　a　high-precision　semi-physical　simulation　platform　for　UAV　visual　navigation　tests.　According　to　the　characteristics　of　the　UAV　and　the　simulation　model,　a　new　six-degree-of-freedom　mechanical　structure　composed　of　a　three-axis　turntable　and　a　three-axis　truss　is　proposed.　This　mechanical　structure　can　simulate　the　flight　attitude　of　a　quadrotor　UAV　within　a　three-dimensional　space　of　4.　0　m　×　2.　0　m　×　1.　4　m.　According　to　the　designed　mechanical　structure　and　its　dynamic　characteristics,　the　control　system　based　on　EtherCAT　communication　is　developed.　The　system　can　realize　real-time　flight　attitude　simulation　in　the　real　physical　environment　and　synchronous　flight　attitude　simulation　in　the　virtual　animation　space.　The　actual　measurement　results　show　that　the　repeated　positioning　accuracy　of　the　three-axis　turntable　can　reach　0.　006毅,　the　repeated　positioning　accuracy　of　the　three-axis　truss　can　reach　0.　033　mm,　and　the　dynamic　error　accuracy　can　reach　0.　04毅　and　0.　4　mm.　The　effectiveness　of　the　simulation　platform　is　also　verified　by　indoor　and　outdoor　comparison　tests.　The　results　show　that　the　simulation　platform　can　meet　the　needs　of　high-precision　UAV　visual　navigation　simulation.　©　2023　China　Ordnance　Society.　All　rights　reserved.