Abstract: Considering the characteristics of space debris, high-speed spinning around its main axis, Single Range Matching Filtering(SRMF) method can be used for ISAR imaging of space debris with small dimension. By introducing coherent CLEAN technique, high sidelobe problem brought by Fourier transform can be solved with SRMF-CLEAN method effectively . However, under the condition of low signal-to-noise ratio, the position error of scattering centers extracted by SRMF-CLEAN method is big, and even some weak scattering centers cannot be extracted. When the distance between the scattering centers is close, some of scattering centers extracted by the method are false. Therefore, an improved SRMF-CLEAN imaging method was proposed in this paper. The method utilizes sequence CLEAN instead of coherent CLEAN to effectively solve the above problems of high sidelobe and false scattering centers. The experiment results verify effectiveness of the proposed method.