We report a simple strategy to prepare 2-dimensional cobalt sulfide by the one-step hydrothermal process. The cobalt sulfide sample has a microstructure of interconnected sheets. As the electrode material for supercapacitors, the layered cobalt sulfide film exhibits superior performances with high specific capacitances (1314Fg −1 at 3Ag −1 ) as well as excellent cycle life (less than 8.3% decrease in specific capacitance after 500 cycles at 3Ag −1 ), making it suitable for high-performance supercapacitor application.