The Li/PVdF/S cell showed the first discharge capacity of 1268mAhg−1, which was about 78% utilization of theoretical value. There were two plateau regions at the first discharge curve. From the XRD, DSC results of the sulfur electrode, elemental sulfur disappeared at the upper plateau region and Li2S was formed at the low plateau region. We suggested the discharge process of Li/polymer electrolyte/S cell. The elemental sulfur changed into Li2S n (n >4) and subsequently changed into Li2S at a lower plateau potential region.