In　the　past　two　decades,　humidity　actuators　have　received　extensive　attention　from　researchers　due　to　their　merits　of　simple　stimulation,　no　pollution,　programmable　actuation　behaviour,　and　simple　structure.　However,　in　order　to　perform　more　complex　and　difficult　tasks,　it　is　indispensable　to　enhance　the　response　speed　of　the　humidity　actuators.　Therefore,　we　mainly　discuss　the　influence　of　materials　and　structure　on　the　response　speed　of　the　actuators　in　this　paper.　In　this　review,　the　materials　of　the　actuators　include　inorganic　materials,　polymers,　biomaterials,　hybrid　materials,　and　structural　materials.　According　to　the　structures,　the　actuators　can　be　divided　into　monolayer　film　and　multilayer　film　types.　In　addition,　the　applications　of　humidity-driven　actuators　in　humidity　detection,　soft　robot,　self-power　and　medical　equipment　are　introduced,　providing　a　reference　for　the　large-scale　application　of　humidity　actuators.　Finally,　this　review　also　considers　the　practical　challenges　faced　by　humidity-driven　actuators,　summarizes　how　these　challenges　affect　the　potential　applications　of　the　actuators,　and　prospects　for　the　future　development　trend　of　the　actuators.