Fog　harvesting　is　one　of　the　effective　ways　to　solve　the　water　shortage,　especially　in　poor　arid　and　semi-arid　areas.　Over　the　last　decade,　various　fog　harvesting　materials　have　been　reported　continuously,　but　most　of　the　materials　have　problems　such　as　the　inability　to　obtain　fog　from　the　fog-harvesting　surface　instantly　and　the　existence　of　secondary　evaporation　of　the　captured　fog.　Inspired　by　the　asymmetric　microgeometry　of　cactus　spines,　the　alternate　hydrophobic/hydrophilic　micropattern　on　the　desert　beetle　back,　the　spindle-knot　of　spider　silk　and　the　asymmetric　wettability　of　lotus　leaf,　we　successfully　designed　a　quadruple　biomimetic　Janus　composite　material　with　asymmetric　microtopology　and　anisotropic　wettability　by　chemical　etching　and　electrospinning.　The　material　achieves　an　excellent　fog　harvesting　efficiency　with　80.57　mg.min(-1).cm(-2)　through　the　efficient　fog　capture　and　unidirectional　droplets　transport.　Besides,　the　secondary　evaporation　of　captured　water　is　greatly　reduced　by　the　material,　and　the　water　retention　rate　can　reach　92.97　%　at　25　degrees　C　and　72.57　%　at　50　degrees　C,　which　is　8.57　%　and　41.49　%　higher　than　the　original　samples,　respectively.　We　believe　it　is　greatly　promising　for　relieving　societal　water　scarcity.