Improving the performance of fuel cell is a research focus. The rough interface between microporous layer (MPL) and catalyst layer (CL) which affects the performance of fuel cell has been simulated by W-M function. The relative heat resistance and the relative diffusivity of the rough contact surface to the perfect contact surface between MPL and CL had been calculated by Monte Carlo simulation. The results show that the relative thermal resistance and the relative diffusivity decrease with the increment of fractal dimension of rough surface. The research results have reference value for fuel cell design.