Abstract: A novel range-spread target detection algorithm in Gaussian clutter is addressed for Stepped Chirp Modulated Radar (SCMR). For SCMR, the High Resolution Range Profile (HRRP) of a target is obtained by target extraction from overlapping HRRPs which is caused by oversampling. During the target extraction (sometimes called de-correlation), some strong scatters of the target echo are discarded, as the result, the Signal-to-Clutter Ratio (SCR) might be reduced and the target detection capability is degraded. To solve this problem, a novel target detection algorithm without target extraction is addressed. The new algorithm based on the power spectrum of echoes uses not only the amplitude information, but also the phase information of the overlapping HRRPs of a target to improve the SCR, therefore, has significant performance. The test statistic and the false alarm probability of the detector are derived. Finally, the detection performance is assessed by Monte-Carlo simulation, and the results indicate that the proposed algorithm is effective. In addition, the proposed algorithm is robust and easy to implement in practical application.