This paper proposes a modeling of fuel cell which replaces dc source during simulation. Fuel cells are electrochemical devices that convert chemical energy in fuels into electrical energy. This system has high efficiency and heat, no environmental chemical pollutions and noise. These fuel cells are consisted of many different materials such as solid oxide fuel cell(SOFC) and proton exchange membrane fuel cell(PEMFC). But these fuel cells have similar electrical characteristics such as a low voltage and high current compared with solar cells. However, there are different behaviors in the V-I curve in the high temperature. Therefore, the modeling of fuel cell should consider wide voltage range and slow current response and the resulting electrical model is applied to power converter system(PCS) with fuel cell as an input source.