The　dilution　water　blending　is　a　key　link　in　the　crude　oil　electrical　desalination　system　of　oil　fields　or　refineries,　which　directly　affects　the　efficiency　and　operating　energy　consumption　of　electrical　desalination.　In　order　to　further　simplify　the　equipment　structure,　reduce　costs　and　increase　system　efficiency,　a　thin　plate　static　mixer　for　dilution　water　mixing　was　proposed.　On　the　basis　of　the　preliminary　structural　design　of　the　thin　plate　static　mixer,　computational　fluid　dynamics　(CFD)　was　used　to　perform　three-dimensional　numerical　simulation　of　oil-water　mixing,　the　square　root　of　segregation　strength　(IOS0.5)　in　a　uniform　mixing　state　and　pipeline　pressure　drop　(Δp)　were　used　as　evaluation　parameter,　which　can　indicate　the　influence　of　structural　parameters　on　the　uniformity　of　oil-water　mixing　and　the　running　energy.　The　structural　parameters　were　the　length　of　water　injection　pipe,　the　distance　between　water　injection　pipe　and　thin　plate,　thin　plate　guide　position　and　the　thickness　of　bending　sheet.　Subsequently,　with　the　inner　diameter　D　of　the　hybrid　pipeline　as　a　reference,　the　key　structural　parameters　were　optimized　by　the　response　surface　method　(RSM),　and　the　mixing　performance　under　the　optimal　combination　of　structural　parameters　was　predicted.　The　optimal　combination　of　structural　parameters　obtained　by　optimization　was　as　follow:　the　length　of　the　injection　pipe　was　1/3D,　the　distance　between　the　center　of　the　injection　pipe　and　the　orifice　was　4/25D,　the　guiding　position　of　the　orifice　was　1/8π,　and　the　thickness　of　the　orifice　was　1/25D.　By　comparing　and　analyzing　the　mixing　effect　of　the　thin　plate　static　mixer　before　and　after　optimization,　it　was　found　that　the　optimized　structure　of　IOS0.5　was　43.06%,　which　was　lower　than　before　optimization.　Qualitative　analysis　of　the　water　phase　velocity　cloud　diagram　and　streamline　diagram　in　the　thin　plate　mixer　showed　that　when　the　water　injection　ratio　was　2%,　the　oil　and　water　two　phases　can　reach　a　uniform　mixing　state　at　the　3D　downstream　of　the　water　injection　pipe.　It　can　be　seen　that　the　thin　plate　static　mixer　can　quickly　achieve　uniform　mixing　of　oil　and　water　at　a　small　water　injection　ratio.　©　2021,　China　Science　Publishing　&　Media　Ltd.　All　right　reserved.