As interferences are introduced from a main-lobe direction, which results in target signals being masked by interference, traditional adaptive beamforming and eigen-subspace projection methods cannot suppress main-lobe interferences effectively. A novel interference suppression method is proposed that processes the sample data by using the scanning property of a single polarized antenna. The orthogonal polarization decomposition and polarization estimation of the receiving signal based on the spatial polarization characteristics of the antenna are realized so that the interference is diminished. The effect of an elevation measurement error on interference suppression performance is eliminated by design spatial multinotch virtual polarization filtering. Theoretical and simulation results show that it made single polarized radar own a polarization information processing ability that improved radar working performance.