Aiming　at　poor　efficiency　of　the　traditional　materials　in　absorption　of　low-frequency　sound　and　its　narrow　bandwidth,　a　low-frequency　broadband　absorption　mechanism　of　the　micro-perforated　lossy　metasurface　is　presented,　and　a　multi-cell　metasurface　is　designed,　in　which　each　cell　is　comprised　of　a　micro-perforated　panel　and　a　coiled-up　cavity.　The　absorption　coefficient　of　a　single　cell　is　firstly　calculated　by　finite　element　simulation　and　theoretical　formulas.　Compared　with　the　traditional　Helmholtz-resonator　structures,　the　present　metasurface　structure　can　gain　multiple　excellent　higher-order　peaks　besides　the　first　peak,　and　each　peak　bandwidth　is　nearly　doubled.　Hence　the　mechanism　is　proposed　to　achieve　low-frequency　and　wide-band　absorption.　The　specific　effects　of　the　typical　parameters　on　the　absorption　performance　are　then　investigated,　including　absorption　area　ratio,　hole　diameter,　cavity　depth,　and　so　on.　By　strictly　coupling　the　peaks　of　the　cells,　an　8-cell　metasurface　is　finally　obtained.　The　results　show　that　the　metasurface　can　achieve　continuous　and　excellent　sound　absorption　in　the　range　of　550-2　500　Hz　with　a　deep-subwavelength　thickness　of　only　6　cm,　and　the　average　absorption　coefficient　reaches　above　90%.　The　proposed　structure　is　characterized　by　the　thin　thickness,　wide　bandwidth　and　high　strength,　and　it　can　be　widely　applied　to　the　noise　reduction　of　anechoic　chambers,　plants　and　aircrafts.　©　2019,　Editorial　Office　of　Journal　of　Xi＇an　Jiaotong　University.　All　right　reserved.