The invention belongs to the field of the radar signal processing technology and discloses a synthetic aperture radar echo simulator and an echo simulation processing method. The simulator comprises an FPGA (field programmable gate array) chip, a DDR (double data rate), a power module, an upper computer, a network interface module, a D / A (digital to analog) module, a high-speed interface module and a data logger. The simulation method includes the steps of configuration parameter writing, full scene equivalent scattering coefficient determination, system impact response component determination and time-frequency transformation, time-frequency transformation of emission signals, inverse time-frequency transformation processing, small scene or large scene echo signal output and large scene echo signal playback. The single FPGA chip, the DDR and the data logger are only adopted for the main structure, the echo simulation process is achieved by the aid of assembly line work, and the synthetic aperture radar echo simulator has the advantages of simple system structure, high reliability, capabilities of effectively increasing the simulation speed of SAR (synthetic aperture radar) small scene echo signals, achieving real-time simulation of small scene echoes and being used for large scene echo signal simulation and echo signal playback and output, and the like.