Dielectric barrier discharge (DBD) actuator which is efficient as a flow controller unexpectedly changes the radar cross section (RCS) of a target. Because plasma generated by DBD can attenuates electromagnetic wave, numerical investigation of 3-D RCS is required to analyze the effect of the plasma actuator on flying vehicles. Simplified plasma modeling is utilized to describe inhomogeneous distribution of DBD plasma. The calculated RCS diagram shows good agreement with experiments. The effect of DBD in monostatic RCS is totally different as the observation plane is changed. It shows notable distortion in the plane which is perpendicular to electrode array while overall pattern is still obviously maintained in parallel plane. It is due to the asymmetry from the electrode arrangement of the actuators and inhomogeneous plasma distribution. 3-D analysis is essential to comprehend the effect of DBD plasma in RCS in order to analyze the dissimilar change in various observation planes.