The　mafic　enclaves　from　Mesozoic　intermediate-acid　magmatic　rocks,　widely　developed　along　Fujian　coast,　are　considered　to　be　the　results　of　large-scale　crust-mantle　interaction　and　magma　mixing.　In　this　paper,　petrography,　mineralogy,　and　geochemistry　of　granites　and　mafic　microgranular　enclaves　(MMEs)　in　Langqi　Island　are　studied　to　provide　new　information　for　tracing　crust-mantle　interaction.　The　zircon　U-Pb　dating　results　show　that　the　Langqi　rocks　were　formed　at　∼101　Ma,　which　are　metaluminous,　enriched　in　silica　and　high-K　calc-alkaline　I-type　granites.　The　enclaves　have　a　typical　magmatic　structure,　which　is　characterized　by　magma　mixing　between　high-temperature　basic　magma　and　low-temperature　acidic　magma　through　injecting.　The　enclaves　and　host　granites　show　a　tendency　to　mixed　major　and　trace　elements,　displaying　a　clear-cut　contact　relationship,　which　is　indicative　of　coeval　magmatism.　The　genesis　of　Langqi　rocks　is　related　to　the　extensional　setting　caused　by　the　subduction　of　Paleo-Pacific　Plate,　and　they　are　the　results　of　mixing　of　subduction-related　metasomatized　mantle-derived　mafic　and　induced　crustal-melted　granitic　magma　originating　from　partial　melting　of　the　crustal　material.　©　2020,　China　University　of　Geosciences　(Wuhan)　and　Springer-Verlag　GmbH　Germany,　Part　of　Springer　Nature.