The　removal　of　oil　mist　is　essential　for　industrial　process　and　worker＇s　occupational　health,　as　the　oil　mist　will　not　only　damage　the　industrial　production　device,　but　also　increase　human　inhalation　exposure　risk.　Traditional　filters　focus　on　high-efficiency　low-resistance　structured　design　for　air　filtration,　while　there　is　little　research　on　cyclically　sustainable　filters　for　oil-mist　filtration.　Here,　we　developed　a　chitosan　aerogel　based　on　sustainable　sandwich　structure　filter　(NW-CS-Nylon　6)　with　thickness-direction　asymmetric　wettability　and　pore　size　differences,　including　polypropylene　nonwoven　fabric,　chitosan　aerogel　and　Nylon　6　nanofibrous　membrane.　Spraycoating　was　used　to　endow　the　Nylon　6　nanofibrous　membrane　with　oleophobicity,　and　provide　the　whole　filter　with　directional　oil-transport　function.　Results　revealed　that　the　initial　filtration　efficiency　and　pressure　drop　of　the　oil-mist　was　99.4%,　0.5　kPa,　respectively.　Remarkably,　the　ultra-high　filtration　efficiency　of　99%　and　98%　was　still　maintained　when　the　filtration　was　carried　out　for　50　and　100　times.　Compared　with　traditional　filters,　it　had　higher　filtration　efficiency　and　lower　pressure　drop　when　continuously　recycled,　which　had　important　research　significance　for　filter　recycling　and　energy　saving　in　the　future.