Lithium sulfur cells were prepared by composing with sulfur cathode (PEO)6LiBF4 polymer electrolyte and lithium anode. (PEO)6LiBF4 polymer electrolyte was prepared under three different mixing conditions: stirred polymer electrolyte (SPE), ball-milled polymer electrolyte (BPE) and ball-milled polymer electrolyte with 10wt%Al2O3 (BCPE). The effects of ball milling and additive were investigated by discharge test according to depth of discharge. The initial discharge capacity of lithium sulfur cell using BCPE was 1670mAhg−1-sulfur, which was better than those of SPE and BPE, and approximately equal to the theoretical capacity. The cycle performance of Li/(PEO)6LiBF4/S cell was remarkably improved by the addition of Al2O3.