The electrochemical performance of lithium-sulfur batteries with LiClO4 DOL/DME as electrolyte was investigated. Impedance and SEM analysis indicated that too high content of DME(Dimethoxy ethane) in electrolyte could raise the interfacial resistance of battery due to the impermeable layer formed on the surface of the sulfur cathode, which led to bad cycle performance, while the increase of DOL(1,3-dioxolane) could change those phenomena. The optimal composition of electrolyte was DME: DOL = 2:1 (v/v). With this electrolyte, the lithium-sulfur battery obtained a high initial discharge capacity of 1,200 mA h g(-1) and still remained 800 mA h g(-1) after 20 cycles.