Aluminum-sulfur　(Al-S)　battery　is　a　promising　candidate　of　next　generation　rechargeable　batteries　owing　to　its　high　theoretical　energy　density,　high　safety　and　low　cost,　but　currently　greatly　impeded　by　the　shortage　of　high-performance　and　cost-effective　electrolytes.　In　this　work,　a　low-cost　deep　eutectic　solvent,　i.e.,　AlCl3/acetamide,　as　the　electrolyte　for　reversible　room-temperature　Al-S　battery　has　been　reported.　The　Al-S　battery　delivers　an　initial　capacity　above　1500　mA　h　g(-1)　and　good　rate　performance,　which　is　most　probably　caused　by　the　presence　of　AlCl4-,　Al2Cl7-　and　[AlCl2　center　dot(acetamide)(2)](+)　ions　as　indicated　by　spectroscopic　analysis.　Furthermore,　X-ray　photoelectron　spectroscopy　on　the　discharged　sulfur　cathode　suggests　the　presence　of　aluminum　sulfides　including　Al2S3　as　electrochemical　conversion　products.　Density　functional　theory　calculations　on　the　energy　barriers　provide　insights　into　the　electrochemical　reaction　pathways.　This　AlCl3/acetamide　based　Al-S　battery　presents　a　promising　prospect　for　high-performance　and　low-cost　energy　storage　system　in　future.