In the squint airborne radars, the range dependence of clutter spectrum degrades the performance of conventional space time adaptive processing for clutter suppression, so a new method is proposed. In this method the similarity measure value is obtained by using the spatial domain steering vector relationship between the range bin under test and under test range bins. The received data of adjacent range bins is weighted by these values.In order to improve the detection performance of airborne radar, the non-homogeneity detector (NHD) is used to mitigate these interferences, and then the conventional STAP is applied to the clutter suppression. Finally,simulation results show that the new method is effective and practical.