Abstract: In practice, the information of under test range bin would leaked into other range bins, since the point spreading function of a target is not an ideal delta function, and leads to the covariance matrix of clutter becomes inaccuracy.Aim at the problem, the new method is proposed in this paper The method firstly reduces the degree of freedom (DOF) of clutter by the time-delay filtering. Secondly, the method makes full use of the correlation among the adjacent range bins to construct a new covariance matrix, which eliminate the influence of diffuse information on covariance matrix and combine the multi-range bins carry through the clutter suppression.Thereby, the new method would suppress clutter effectively.Lastly, the measure data is processed by the new method.Its analysis shows that approach improved processing of effectiveness