Due　to　the　urgent　need　for　heat　dissipation　of　high　heat　flux　devices　in　many　engineering　applications　to　maintain　high　performance　and　stable　operation,　flow　boiling　in　micro/mini-channel　heat　sinks　is　an　enabling　and　promising　approach　to　tackling　high　heat　flux　cooling　issues　in　emerging　cutting-edge　technology.　Various　enhancement　techniques　for　flow　boiling　in　micro/mini-channels　have　been　investigated　in　recent　years.　These　mainly　include　various　surface　modifications,　enhanced　channel　structures　and　composite　enhancement　techniques.　These　techniques　are　able　to　improve　flow　boiling　heat　transfer　coefficient　(HTC),　critical　heat　transfer　(CHF)　and　mitigate　two　phase　flow　instabilities.　The　composite　enhancement　techniques　take　the　advantage　of　each　individual　technique　for　flow　boiling　to　achieve　more　efficient　heat　transfer　and　stable　flow.　However,　there　are　challenges　to　optimizing　these　techniques　and　understanding　the　very　complex　mechanisms　involved　in　these　emerging　techniques.　This　paper　presents　a　comprehensive　review　of　the　studies　of　various　enhancement　techniques　for　flow　boiling　and　mechanisms　in　micro/mini-channels　having　hydraulic　diameter　of　0.1-3　mm　over　the　past　five　years.　First,　the　criteria　for　distinction　of　micro/mini-channels　and　classification　of　flow　boiling　enhancement　techniques　are　discussed.　Then,　studies　of　flow　boiling　enhancement　techniques　using　surface　modification　techniques　and　enhanced　structures　are　critically　reviewed.　Next,　the　effects　of　surface　modification　techniques　and　enhanced　structures　on　flow　boiling　heat　transfer,　CHF,　two　phase　flow　patterns,　two　phase　flow　instability　and　mechanisms　in　micro/mini-channels　are　discussed　and　analyzed.　Other　enhancement　techniques　such　as　using　surfactants　to　enhance　flow　boiling　is　also　mentioned.　Finally,　future　research　needs　have　been　identified　and　recommended　according　to　the　comprehensive　review　and　deep　analysis.　Systematic　research　on　the　physical　mechanisms　underlying　the　composite　heat　transfer　enhancement　techniques　is　urgently　needed.　Optimization　design　of　micro/mini-channel　flow　boiling　heat　transfer　enhancement　techniques　is　a　big　challenge　and　should　be　focused　on　in　future.　In　order　to　understand　the　mechanisms,　the　bubble　dynamics,　bubble　nucleation　and　flow　patterns　of　flow　boiling　in　the　composite　enhancement　techniques　in　micro/mini-channels　should　be　systematically　investigated　to　understand　the　mechanisms　and　optimizing　the　enhancement　techniques.　Effort　should　be　made　to　develop　prediction　methods　for　flow　boiling　heat　transfer　and　CHF　in　the　long　run.