Abstract: ‍ ‍For pulse-compression radar waveforms， higher range side lobes will result in the target masking effect. Low range sidelobe radar waveform design is an important research on radar waveform. The existing low-range sidelobe waveform designs are all based on full-pulse correlation. This paper uses the method of waveform combination to design the waveform. Based on the frequency-domain orthogonal design， two or more sub-pulses of complementary sequences are modulated to different frequency points and then combined into a constant-modulus monopulse radar waveform. Different from full-pulse matched filtering， this paper presents a single-pulse intra-pulse segmental pulse compression signal processing method， which makes full use of the autocorrelation characteristics of complementary codes. The simulation test shows that the peak sidelobe level and the integral sidelobe level of the designed waveform after pulse compression are low， and can even break through the lower limit of the peak sidelobe level of some phase-encoded signals， but there will be main-lobe broadening and 0.89 dB energy loss. Compared with the chirp signal， the radar waveform proposed in this paper does not cause the sidelobe of the strong target to mask the weak target. The constant false alarm detection simulation shows that the detection probability of the waveform in this paper is better than that of the chirp signal.