Flume　experiments　were　conducted　to　study　the　mechanics　of　equilibrium　sediment　transportation　based　on　image　processing　technique,　PTV　method　and　Kalman　Filters　algorithm.　On　this　basis,　the　three-dimensional　bed　surface　topography　reconstructed　by　SFM　was　compared　with　particle　movement　to　study　the　interaction　mechanism　between　sediment　particle　movement　and　turbulent　coherent　structure.　The　results　show　that:　(1)　The　method　in　this　paper　can　be　applied　to　recognize　the　sediment　particle　trajectories　in　the　particle　scale,　which　provides　a　new　idea　for　studying　mechanics　of　bed-load　transport.(2)　Under　the　certain　flow　conditions(Θ=0.048,　0.06),　sediment　movement　intensities　has　a　high　and　low　alternating　streaky　structure　along　the　spanwise　direction,　reaching　its　maximum　at　the　center　and　decreasing　gradually　toward　the　side　wall.　(3)　When　the　alternating　ridges　and　troughs　structure　formed　on　the　bed　surface,　the　bed　load　motion　intensity　is　high　in　the　ridge　region　and　low　in　the　trough　region.　(4)　The　streamwise　vortices　model　can　well　explain　the　characteristics　of　sediment　movement　intensity　and　sediment　streaks　alternating　in　the　spanwise　direction.　The　time-averaged　bed　structure　is　formed　by　the　coupling　interaction　of　sediment　streaky　structure　and　super-streamwise　vortices.　©　2020,　China　Water　Power　Press.　All　right　reserved.