The electrochemical properties of sulfur cathode with Ni foam current collector are investigated in detail. Different from sulfur cathode with stain steel current collector, it is interesting found that novel redox peaks at 1.95 V/1.35 V are observed for sulfur cathode with Ni foam. The electrochemical behavior is further verified by ex-situ XRD, SEM and XPS analyses. The results indicate that Ni foam current collector is involved in the redox reaction in Li/S rechargeable battery, and NiS forms at the surface of the Ni foam. These results demonstrate that the sulfur electrode is transformed into NiS.