Abstract: In order to detect the targets in the first-order sea clutter spectrum of high frequency surface wave radar (HFSWR), a method based on singular value decomposition (SVD) is proposed to suppress sea clutter in spatial domain. The sea clutter suppression method is based on the strong correlation of sea clutter, thus we take the adjacent range bin as the reference. Then the sea clutter subspace and noise subspace in the spatial domain is estimated by singular value decomposition of its array covariance matrix. Finally, we subtract its projection in the sea clutter subspace from the array signal with the orthogonality of subspace, and achieves the purpose of suppressing sea clutter in the spatial domain. Compared with the existing methods of sea clutter suppression in spatial domain, there is no need to know the azimuth of sea clutter in advance. The subspace is estimated by singular value decomposition of its array covariance matrix, which makes it easier and more accurate to estimate the sea clutter subspace and noise subspace. The result shows that the method improves the signal to clutter plus noise ratio (SCNR), which is benefit to target detection.