Abstract: Dual-Functional Radar-Communication (DFRC) system based on Frequency Modulated Continuous Wave (FMCW) has the characteristics of high time-frequency utilization, strong anti-Doppler performance and low range sidelobe. The existing FMCW-DFRC waveform designs generate dual-function deterioration and increase the link complexity of communication receivers. A DFRC system based on Delayed Breakpoint Mapping (DBM)-FMCW is designed to modulate data by mapping the location of the delayed breakpoint in the chirp period and the phase between the divided clusters. After carrier mixing and undersampling, dechirping, chip alignment and data demodulation are realized in the digital domain. In the radar processing link, a Breakpoint Area Deletion and Splicing (BADS) scheme is designed to make the radar performance of DFRC consistent with that of unmodulated FMCW. The simulation results show that, compared with the uncompensated scheme, the BADS scheme can reduce the sidelobe amplitude of the image by about 37 dB and is not affected by the modulation data. Compared with the communication performance of existing DFRC schemes based on chirped waveform, DBM-FMCW reduces the symbol error rate.