In　recent　years,　tube-in-tube　membrane　microreactors　have　greatly　improved　gas-liquid　mass　transfer　and　reaction　rates　due　to　their　advantages　such　as　short　mass　transfer　distance,　large　gas-liquid　contact　area　and　high　gas　permeability.　They　are　regarded　as　a　powerful　tool　to　accelerate　the　study　of　gas-liquid　mass　transfer　and　flow　reaction　processes.　At　present,　the　tube-in-tube　reactor　has　been　widely　used　to　establish　a　fast　and　accurate　flow　measurement　platform　for　gas-liquid　physical　parameters,　achieve　efficient　and　safe　gas-liquid　reaction　processes,　and　enhance　gas-mediated　biological　enzyme　catalytic　reaction　processes.　In　this　review,　a　detailed　description　and　construction　method,　and　the　recent　advancements　in　this　reactor　are　provided.　Finally,　based　on　current　research　hotspots,　a　perspective　on　future　potential　applications　filed　of　such　flow　reactor　is　discussed.　©　2024　Materials　China.　All　rights　reserved.