Micro　flow-focusing　devices　were　widely　used　in　the　synthesis　of　particulate　material,　drug　packaging,　cell　culture　and　other　areas　owing　to　the　convenience　and　effectiveness　to　produce　highly　monodisperse　and　precisely　sizecontrollable　droplets.　To　optimize　the　channel　structure　and　geometry　parameters　deeply　is　of　benefit　to　achieve　the　precise　regulation　of　droplets＇　diameter,　uniformity　and　the　size　ranges.　For　the　adaptive　design,　channel　depth,　orifice　length　and　the　angle　in　continuous　and　discrete　phase　are　taken　into　account　to　investigate　the　influence　of　geometry　configurations　on　the　microdroplet　diameter　and　its　generated　cycle　stages　in　flow　focusing　microchannel　by　making　use　of　numerical　simulation.　It　is　shown　that　the　droplet　diameter　approximately　increases　linearly　with　the　channel　depth,　meanwhile,　when　the　channel　depth　is　less　than　30　μm,　the　droplet＇s　cycle　increases　suddenly　under　the　application　of　strong　capillary　force.　The　microdroplet　diameter　and　its　cycle　are　both　the　shortest　while　the　angle　of　the　continuous　phase　and　discrete　phase　θ　is　nearly　90°,　and　too　large　or　too　small　angles　are　both　not　conductive　to　generate　droplets　with　uniform　diameter　and　well　controlled　particle　size.　Orifice　length　is　used　to　adjust　the　alteration　of　the　microdroplet　diameter　and　its　cycle,　which　lead　to　the　average　rangeability　within　3%~5%.　In　addition,　the　width　of　orifice　region　is　an　important　factor　a　ecting　the　microdroplet　diameter　and　its　cycle　in　cross　microchannel.　When　the　channel　depth　is　fixed,　the　wider　the　orifice　region　is,　the　greater　the　microdroplet　diameter　and　its　cycle　are.　©　2016,　Editorial　Office　of　Chinese　Journal　of　Theoretical　and　Applied　Mechanics.　All　right　reserved.