In post-Doppler processing methods of STAP, the correlation between the channels is ill advised, and leads to the covariance matrix of clutter becomes inaccuracy. Aim at the problem, a new post-Doppler processing STAP 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 Doppler bins to construct a new covariance matrix, which improve the ability of adaptive in the domain of time and release the burden of clutter suppression in the domain of spacing, eliminate the influence of diffuse information on covariance matrix and combine the multi-Doppler 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.