Because of its long signal duration and duty cycle of 1, compared to traditional pulse radar,FMCW radar no longer requires high peak transmit power,which reduces the design difficulty of radar transmitters. This article is a combination of FMCW and synthetic aperture radar, Through the cutting and recombination of FM continuous wave, Through the cutting and recombination of FMCW, The signal code group with excellent orthogonality and cross-correlation can be obtained. Through simulation, it can be verified that the code group has good characteristics.