Abstract: To verify the correctness of echo generation and imaging algorithm, it is necessary to evaluate the bistatic synthetic aperture radar(BiSAR) imaging result quantitatively. Because the azimuth resolution direction is not normal to the range resolution direction in a BiSAR system, an equivalent approach for evaluating the BiSAR point target image is proposed and introduced. The approach can search the side-lobe direction automatically after 2D interpolation, and then evaluate the BiSAR point target image along the side-lobe direction. The corresponding evaluation result is verified by computer simulation.