Mesoporous titanium dioxide sub-microspheres (MS TiO2) have been prepared by a facile one-step hydrothermal synthesis method with the existence of 1-carboxyethyl-3-methylimidazolium chloride ionic liquid ([HOOCEMIM][Cl](IL)). The [HOOCEMIM][Cl](IL) used in the experiment played a crucial role in triggering self-assembly of primary TiO2 nanoparticles. The obtained MS TiO2 material has an excellent porous structure with a large pore volume of 0.792cm3 g−1 and a large specific surface area of 291.08m2 g−1. This unique structure can realize effective contact between host material and lithium polysulfide intermediates, thus promote the adsorption performance chemically. In addition, the 3D mesoporous structure can physically confine the intermediate products to the electrode and also accommodate the volume expansion of sulfur upon cycling. The MS TiO2 and sulfur (MS TiO2-S) composite cathode exhibited superior rate capacity and long term cycling stability than that of the commercial TiO2 and sulfur (C TiO2-S) composite cathode, displaying a very low capacity decay rate of 0.07% per cycle over 300 cycles. Even when the sulfur content of the MS TiO2-S composite is up to 84wt.%, the capacity decay rate still remains at a relatively low level.