Overview: This paper is devoted to the research of synthetic aperture radar (SAR) real-time imaging processor. As the number of SAR imaging channels increases, the number of SAR imaging channels also presents new challenges. The optical processor not only has strong parallel processing ability, but also has the advantages of low power consumption, small volume, fast processing speed and programmability. Therefore, this paper designs and analyzes the SAR real-time imaging optical processor from the perspective of optical mechanical system design. Firstly, the system scheme principle of optical processor based on 4f optical structure is proposed, and the filtering algorithm is described in detail according to the principle. Secondly, according to the algorithm requirements, the relevant Fourier transform lens design is completed, and the compactness of 4f optical system is further strengthened. Then, the flexible design of the lens base is carried out, and the optimal parameter model is found by using the integrated optimization method. At the same time, it meets the modular design idea, completes the corresponding optical mechanical structure design, and obtains the optical mechanical system model of the overall scheme. The specific design results obtained based on the above research methods are as follows: in the optical design process, a Fourier transform lens with an entry pupil diameter of 21 mm, a field angle of 7°, and a focal length of 172 mm is obtained, and its MTF is better than 0.57 at 55 lp/mm. And the 4f optical system whose imaging quality tends to the diffraction limit meets the Rayleigh criterion. In the process of optical mechanical structure design, the overall size of 4f optical mechanical system is 405 mm×145 mm× 92 mm, with a mass of about 2.94 kg, and its volume and mass are only 30% and 48% of that of the inclined plane optical processor with the same SAR data processing level; At the same time, the RMS value of lens surface under normal temperature 1g gravity condition is less than λ/50(λ= 532 nm), the fundamental frequency of the overall structure is greater than 100 Hz, which can fully meet the expected design goal of the processor optical mechanical system. Finally, the simulation processing of SAR data is carried out on the optical platform. According to the simulation results, it shows that the system can be suitable for airborne or spaceborne real-time processing scenes. To sum up, the 4f optical processor designed in this paper can provide a certain reference value for improving the real-time imaging processing ability of SAR. In order to further improve the real-time imaging processing ability of synthetic aperture radar (SAR) in the face of massive echo data, the optical and mechanical system of SAR real-time imaging optical processor is designed and analyzed based on 4f optical structure. Firstly, a Fourier transform lens with an entrance pupil diameter of 21 mm, a field angle of 7°, and a focal length of 172 mm is designed for the filtering algorithm, and a compact design is adopted for the 4f optical system. Then, the flexible mirror base in 4f optical mechanical structure is optimized by using the integrated optimization method, and the overall structure is modularized designed and analyzed. The results show that the imaging quality of 4f optical system tends to the diffraction limit, and the MTF of Fourier transform lens is better than 0.57 at 55 lp/mm. The RMS value of lens surface shape of 4f optical mechanical system under normal temperature 1g gravity condition is less than λ/50. The fundamental frequency of the overall structure is greater than 100 Hz. The overall size of 4f optical processor is 405 mm×145 mm×92 mm, the mass is about 2.94 kg, and its volume and mass are only 30% and 48% of those of oblique plane optical processors with the same SAR data processing level. Through data simulation, it shows that the system design meets the needs of real-time imaging on satellite or airborne.