Abstract: For confronting the anti-radiation missiles (ARM)， Aerial defence Radar often uses Active-Decoying. It is possible that ARM confronts with active-decoying， when high-resolution measurement capability of the spatial spectrum direction-of-arrival (DOA) estimation is used by passive-radar-seeker(PRS). To improve the precision and the stabilization of the angle-measure in the active-decoying environment， a grey processing approach of the passive-radar-seeker is proposed in this paper. The approach based on grey theory and norm， from the view of the topology of the sample space and the distances between samples. Using approach of converted measurements and data windows get the sample space. Using grey data processing approach based on the definitions of grey distance measure and grey relation entropy， eliminate singularity and retain random error. Finally， the simulation test verifies that the grey processing approach can improve the precision and stabilization of anglemeasurer in active-decoying environment， and can improve the precision of ARM.