Intermediate frequency injection type SAR real-time imaging test method and system

The invention discloses an intermediate frequency injection type SAR real-time imaging test method and system, and the method comprises the steps: generating an echo data file according to the actual measurement motion track of a platform and the characteristics of a target scattering point; downloading the echo data file to an intermediate frequency signal playing unit through an external control computer, and externally accessing a pulse synchronization signal and a frame trigger signal of the tested SAR imaging equipment to a corresponding interface of the intermediate frequency signal playing unit; after receiving the frame triggering signal, the intermediate frequency signal playing unit plays an echo signal according to the pulse synchronizing signal, and the echo signal is injected into the tested SAR imaging equipment; the tested SAR imaging equipment outputs an SAR imaging result through the optical fiber port, the SAR imaging result is accessed to the light injection part, the light injection part t