Abstract: ‍ ‍To avoid the Signal-to-Noise Ratio （SNR） loss due to window weighting for sidelobe suppression in the uniform Stepped Frequency Continuous Wave （SFCW） pulse compression， the non-uniform stepped frequency waveform based on window function is proposed. First， the total bandwidth and the number of stepped pulses is obtained according to the desired geometric resolution and the maximum detection distance， respectively. Afterwards， the stepped frequency variation law is designed based on a selected weighting window function for the desired sidelobe level， and the quantization interval of the non-uniform stepped frequency is chosen according to the survey scope. The designed non-uniform stepped frequency waveform presents the characteristics that small pulse stepped frequency intervals in the middle and large stepped intervals in both sides of the duration. For the pulse compression of the designed waveform， the Non-Uniform Fast Fourier Transform （NUFFT） without window weighting is applied to obtain low sidelobes， which avoids the SNR loss due to window weighting. Processing results on both simulated point targets and real raw data validate the non-uniform stepped frequency waveform design method.