Composite　fillers　containing　efficient　xylene-degrading　bacteria　with　nutrient　slow-release　function　were　prepared　by　microbial　immobilization　technique,　using　diatomaceous　earth　(DE)　as　the　backbone,　and　polyvinyl　alcohol　(PVA)　and　sodium　alginate　(SA)　as　immobilization　materials.　A　biotrickling　filter　(BTF)　was　loaded　with　the　composite　fillers　and　the　xylene　purification　performance　was　investigated.　The　specific　surface　area　of　the　composite　filler　was　4.53m2/g,　which　had　good　water-holding　capacity,and　the　composite　filler　showed　good　reusability　with　the　removal　efficiency　maintaining　above　95%　after　continuous　treatment　of　8　batches　of　pollutants.　After　11　d　of　operation,　the　outlet　concentration　of　the　BTF　loaded　with　composite　filler　was　below　the　emission　limit　[ρ(xylene)=70mg/m3]　specified　in　GB　16297—1996,　which　indicated　that　the　start-up　of　the　BTF　was　completed　at　this　time.　When　the　inlet　concentration　was　1200　mg/m3　and　the　empty　bed　residence　time　(EBRT)　was　53s,　38s　and　28s,　the　removal　efficiency　was　98%、　86%　and　78%,　respectively.　When　the　EBRT　was　28s　and　the　inlet　concentration　was　700mg/m3and　250mg/m3,　the　removal　efficiency　was　91%　and　99%,　respectively.　When　no　additional　nutrients　were　provided　for　9d,　the　removal　efficiency　did　not　decrease　significantly.　When　the　system　was　stagnated　for　2d　and　7d,　the　performance　could　be　restored　within　9.5h　and　1d　of　operation,　respectively.　The　results　showed　that　the　composite　fillers　had　better　physicochemical　properties,　good　removal　performance　for　xylene,　and　strong　resistance　to　shock　loading　and　stagnation,　which　can　provide　some　reference　value　for　its　application.　©　2023　Chemical　Industry　Press.　All　rights　reserved.