Silicone dioxide (SiO2) layer as an electrical insulator and diffusion barrier was deposited on a flexible stainless steel substrate by plasma enhanced CVD process. And we deposited Mo/Na-doped Mo bi-layer back contact on the oxide layer in order to supply Na into the CIGS absorber. Then we deposited CIGS layer by three-stage process using elemental co-evaporation method and completed the solar cell fabrication. Without antireflection coating, the best CIGS solar cell on the stainless steel showed the conversion efficiency of 10.57 % with Jsc = 33.38 mA/cm and V oc = 0.519 V and FF = 0.61 for an active area of 0.45 cm.