Continuous　vapor　liquid　two-phase　flow　means　that　both　subcooled　single　phase　and　saturated　flow　boiling　always　exist　in　microchannels　with　the　moving　interface　between　them.　The　instable　boiling　phenomena　and　mechanisms　are　very　complicated　and　needed　to　be　deeply　investigated　and　well　understood.　In　the　present　study,　both　experiments　and　dynamics　simulation　of　the　continuous　two-phase　instable　boiling　in　multiple　parallel　microchannels　were　systematically　conducted.　In　the　experimental　aspect,　characteristics　of　the　unstable　flow　boiling　in　the　microchannels　were　experimentally　investigated　using　acetone　as　the　working　fluid　and　flow　boiling　processes　were　visualized　with　a　high　speed　video　camera　simultaneously.　The　test　section　includes　16　parallel　microchannels　having　a　hydraulic　diameter　of　104.3　mu　m.　The　test　mass　flux　ranged　from　437.2　to　868.1　kg/m(2)　s　and　the　test　heat　flux　ranged　from　0　to　100　W/cm(2).　The　measured　flow　boiling　heat　transfer　coefficients　and　two-phase　frictional　pressure　drops　are　analyzed　according　to　the　observed　flow　phenomena　and　mechanisms.　They　were　further　compared　to　the　existing　flow　boiling　heat　transfer　and　two-phase　pressure　drop　prediction　methods.　The　top　three　flow　boiling　heat　transfer　methods　predict　more　than　65%　of　the　heat　transfer　coefficients　within　+/-　30%　while　the　top　two　pressure　drop　methods　only　predicted　43%　of　the　measured　data　within　+/-　30%.　It　shows　that　the　continuous　two-phase　instable　boiling　mainly　occurs　at　the　mass　flux　larger　than　607.6　kg/m(2)　s　and　the　heat　flux　larger　than　30　W/cm(2).　The　backflow　causes　instability　of　the　liquid　and　the　two-phase　interface　which　change　the　thermal　resistances　of　the　fluid.　In　the　theoretical　aspect,　a　dynamic　simulation　model　was　developed　by　using　the　thermal　network　method　and　was　used　to　simulate　the　dynamic　process　of　the　instable　boiling　process.　The　simulated　results　were　compared　to　the　experimental　data　in　this　study　and　from　the　literature　and　the　relative　errors　are　within　+/-　24.4%.　According　to　the　simulation　and　analysis,　the　mechanisms　are　that　the　axial　thermal　conduction　in　the　channel　walls　generates　a　negative　differential　zone　in　the　heat　power　characteristic　curves,　where　the　wall　temperature　decreases　with　increasing　the　heat　flux　in　the　negative　differential　zone.　In　order　to　suppress　the　oscillations　in　the　boiling　process,　it　is　essential　to　eliminate　the　negative　differential　zone.　Enhancing　single　phase　forced　convection　heat　transfer　by　100%　or　enhancing　flow　boiling　heat　transfer　by　50%　can　suppress　the　continuous　two-phase　instable　boiling　in　the　microchannels.　Elongating　the　microchannel　length　and　enhancing　the　axis　thermal　conduction　can　reduce　the　amplitudes　of　the　oscillations　by　60-80%　at　the　conditions　of　G　=　700　kg/m(2)s,　q(eff)　=　70　W/cm(2)　and　T-in　=　30　degrees　C.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.