The special requirements of an Electro-Optical(EO) image seeker for large scanning angle of small window, and the Multidisciplinary Design Optimization(MDO) design method was used in the overall design to get the optimum solution. The subspace parallel design with multi-scheme rapid conceptual design was carried out, and through the permutation, combination, and optimization, these schemes could be transferred to the constraints of engineering design, and distributed the design weight of opto-mechanical structure and servo stabilization system. Then the design schemes were dynamically assessed and iteration optimized, and got the final scheme of gyro stabilized mirror objective space scanning: the scanning range is -20°-10°(pitch)/+15°(azimuth), the window area is no more than 2 times of the entrance pupil aperture, and satisfied the dimensional requirements and the image stabilization ability with high-precision and high dynamic range. The image obtained by flying test is almost the same as the ground static test image, and proves that MDO has the effect and superiority of rapid development of the EO stabilized platform.