In order to achieve the purpose of real-time imaging processing of synthetic aperture radar (SAR) data, based on the use of spatial light modulator (SLM), a SAR data real-time imaging oblique plane optical processor is designed, and the optical path is adjusted to ensure image quality and reduce the volume occupied by the system. First, SLM is used to replace the film in the traditional oblique plane processor to reduce the photoelectric conversion rate of SAR data. Then, the structural parameters of the optical processor are set according to the known SAR related data. According to the horizontal and vertical reduction ratio of SAR, a cylindrical lens that meet the required magnification is designed, and a spherical lens is designed according to the overall length of the cylindrical lens to ensure that the cylindrical lens has sufficient working space. After the design is completed, the optical path is adjusted to reduce the volume occupied by the system, which is compact and lightweight for easy use on spaceborne or on board. The design results show that the system MTF is greater than 0.4 in the cut-off frequency, which meets the imaging requirements. After the optical path is optimized and adjusted, the total length is changed from 1 400 mm to about 700 mm. The results meet the design requirements and actual use requirements.