The　paper　presents　a　comprehensive　review　of　fundamentals　and　engineering　applications　of　CO2　flow　boiling　heat　transfer,　flow　patterns　and　two-phase　pressure　drops　in　macro-　and　micro-channel　evaporators.　First,　distinctions　of　macro-　and　micro-channels　are　discussed.　Second,　the　review　addresses　the　extensive　experimental　studies　on　CO2　flow　boiling　heat　transfer　and　two-phase　flow　in　macro-　and　micro-channels.　The　effects　of　the　physical　properties　on　flow　boiling　heat　transfer,　flow　patterns　and　pressure　drops　are　analysed　by　simulations　using　various　physical　property　packages.　Furthermore,　analysis　of　the　existing　experimental　studies　of　flow　boiling　heat　transfer　is　presented　and　the　physical　mechanisms　are　discussed.　Next,　generalized　CO2　flow　pattern　map　and　flow　pattern　based　mechanistic　flow　boiling　heat　transfer　and　two　phase　pressure　drop　models　specially　developed　for　CO2　are　discussed.　New　experimental　database　of　flow　boiling　heat　transfer　and　diabatic　two　phase　frictional　pressure　drop　have　been　set　up　to　evaluate　the　models.　Comparative　results　of　the　flow　pattern　map,　heat　transfer　and　pressure　drop　models　to　the　experimental　database　are　analysed.　In　addition,　studies　of　CO2　flow　boiling　in　enhanced　channels　are　summarized.　The　oil　effects　on　the　flow　boiling　heat　transfer　and　two　phase　frictional　pressure　drop　are　analyzed　and　simulated　as　well.　According　to　the　extensive　analysis,　the　physical　mechanisms　and　prediction　models　of　the　CO2　flow　boiling　heat　transfer　and　two　phase　flow　phenomena　in　evaportaors　have　been　well　understood.　In　the　aspect　of　engineering　application,　comparisons　of　simulation　results　and　the　experimental　data　in　the　real　thermal　systems　are　discuseed.　Furthermore,　research　need　of　CO2　evaporators　is　discussed.　Some　practical　design　methods　of　CO2　evaporators　are　recommended　according　to　the　analysis.　Finally,　the　potential　application　of　CO2　for　high　heat　flux　cooling,　thermal　and　power　systems　are　also　discussed.　Future　research　needs　in　flow　boiling　heat　transfer　and　two　phase　flow　of　CO2　in　evaporators　and　engineering　applications　are　discussed　and　recommended　according　to　this　comprehensive　review.