In this paper, the linear and nonlinear sea surfaces are constructed to comparatively study the radar scattering characteristics of the two surfaces, using the first-order small slope approximate (SSA) method to calculate the normalized radar cross section (NRCS). Simulation results demonstrate that the nonlinear surfaces have sharper wave crests and shallower troughs than those of the corresponding linear surfaces and the average bistatic NRCS calculated from nonlinear surfaces is larger than the relevant linear surface result except for the scattering angles near the specular direction. In particular, the nonlinear surface backscattering coefficient has larger mean value and associated standard deviation than its linear surface counterpart, and this discrepancy grows bigger as the incident angle increases.