Micromixing　efficiency　is　an　important　parameter　for　evaluating　the　multiphase　mass　transfer　performance　and　reaction　efficiency　of　microreactors.　In　this　work,　the　novel　curved　capillary　reactor　with　different　shapes　was　designed　to　generate　Dean　flow,　which　was　used　to　enhance　the　liquid–liquid　micromixing　performance.　The　Villermaux–Dushman　probe　reaction　was　employed　to　characterize　the　micromixing　performance　in　different　curved　capillary　microreactors.　The　effects　of　experiment　parameters　such　as　liquid　flow　rate,　inner　diameter,　tube　length,　and　curve　diameter　on　micromixing　performance　were　systematically　investigated.　Under　the　optimal　conditions,　the　minimum　value　of　the　segmentation　factor　XS　was　0.008.　It　was　worth　noting　that　at　the　low　Reynolds　number　(Re　＜　30),　the　change　of　curved　shape　on　the　capillary　microreactor　can　significantly　improve　the　micromixing　performance　with　XS　reduced　by　37.5%.　Further,　the　correlations　of　segment　index　XS　with　dimensionless　factor　such　as　Reynolds　number　or　Dean　number　were　developed,　which　can　be　used　to　predict　the　liquid–liquid　micromixing　performance　in　capillary　microreactors.　©　2024　The　Chemical　Industry　and　Engineering　Society　of　China,　and　Chemical　Industry　Press　Co.,　Ltd