A two-dimensional fractional Brown motion (fBm) fractal model is presented, which is suitable for describing the natural rough surface. Using the Kirchhoff approximation, the expressions of the electromagnetic scattering field and the normalized radar cross section from this fractal surface are obtained. Numerical results of the normalized radar cross section as a function of the fractal dimension, characteristic length and incidence frequency are given. Our fBm model is also compared with classical models of Gaussian and exponential correlation.