Aiming at high autocorrelation sidelobe existing in using radar signal modulated by communication information to improve communication data rate of radar under low duty cycle pulse transmission, an integrated radar and communication signal format based on nonlinear frequency modulation (NLFM) signal is proposed. At first, by combining the continuous phase modulation (CPM) and the NLFM signal, the model of the NLFMCPM integrated signal is established. Then, based on the radar autocorrelation performance criterion and the resolution criterion, with the matched filter approach, the impact of the modulation parameters of the integrated signal on radar detection performance is analyzed. Finally, the impact of modulation parameters on communication performance is analyzed. The simulation results show that under the premise of not losing the radar mainlobe energy, range resolution, velocity resolution and maintaining the reliability of communication, the proposed signal can make the autocorrelation sidelobe less than -35 dB.