The invention discloses an electrolyte solution for a lithium-sulfur battery. The electrolyte solution comprises an electrolyte lithium salt, an ionic liquid, a non-solvent liquid and an additive, wherein the viscosity of the non-solvent liquid is lower than that of the used ionic liquid; the solubility of the lithium salt and polysulfide lithium formed in charge and discharge processes in the non-solvent liquid is much lower than the corresponding solubility in the ionic liquid; the additive is another lithium salt with a film-forming function, which is different from the electrolyte lithiumsalt; and fluorinated ether can be selected as the non-solvent liquid. The electrolyte solution mainly aims at developing a complementary synergistic effect of the ionic liquid and the non-solvent liquid; and through assist of the film-forming lithium salt, on one hand, the viscosity of an ionic liquid-based electrolyte solution is reduced and the ionic conductivity of the electrolyte solution isimproved, and on the other hand, the capacity of the electrolyte solution for inhibiting dissolving and shuttling of the polysulfide lithium is strengthened. By adopting the electrolyte solution disclosed by the invention, various negative effects, caused by the polysulfide lithium, to the lithium-sulfur battery are greatly avoided, and the properties, such as the capacity, the cycle performance and the rate capability of the battery are improved as a whole.