The present disclosure provides a SAR system based on the FM continuous wave system, including: a transceiver antenna; a radio frequency module, connected to the transceiver antenna, including a transmitting channel, a receiving channel, a frequency source, and a power amplifier module; a digital module, connected to the radio frequency module, including Control module, timing and timing module, AD module, DA module and recording module; image processing module, connected to the digital module, including motion compensation module and imaging processing module. The SAR system is constructed using the frequency modulation continuous wave system, and the main performance parameters of the system are designed based on the FMCW system, which meets the advantages of simple structure, small size, light weight, and low cost of the system, and has high distance resolution. And combined with the actual application requirements, the processing method of the radar system is designed to meet the application requirements of many fields such as military reconnaissance, geological survey, topographic mapping, marine survey, agricultural and forestry survey, etc.