Abstract: Most of spatial spectrum estimation methods fail when there is only one valid snapshot. To deal with this issue, a pseudo covariance matrix construction model utilizing array receiving signal is proposed. Theoretical analysis shows that the presented model, which consists in the existing methods, is more flexible and general. Combining with beam forming idea, a method based on weighted summarizing is proposed, which considers both the affections of signal-to-noise ratio and array freedom. Estimation performance can be enhanced in some degree. Theoretical analysis and simulation results verify the correctness and effectiveness of the proposed method and model.