Bistatic radar cross sections (RCS) of NACA0012 and a square-pole of metal are computed with 2D FDTD program. Numerical results are consistent with those of literature available. Hence the 2D FDTD program is shown correct and effective. Calculations are performed for the bistatic RCS of 2D wings, sweepback-wings and triangle-wings. These results show that wings with different figure have different profiles of RCS and varying angle χ causes the change of sweepback-wing' and triangle-wing's RCS. The requirement of reducing RCS could be reached through choosing different figure of wing or varying χ according to the design demand.