Based　on　the　problem　that　the　minimum　variance　distortionless　response　(MVDR)　beamformer　is　very　sensitive　to　the　mismatch　of　the　steering　vector,　an　effective　method　of　suppressing　the　interference　sound　sources　is　proposed　in　this　paper.　First,　the　bandwidth　of　speech　signal　is　divided　into　multiple　sub-bands,　and　the　direction　of　arrival　(DOA)　of　sound　sources　at　each　sub-band　is　estimated　by　the　focusing　signal　subspace　method.　Specially,　the　initial　DOA　of　each　sound　source　is　estimated　via　statistical　histogram.　Second,　in　order　to　reduce　the　mismatch　of　the　steering　vector,　based　on　the　spatial　sparsity　of　sound　sources,　the　cost　function　used　for　the　steering　vector　estimation　of　the　target　sound　source　is　constructed　by　Capon　power　so　that　the　steering　vector　of　the　target　sound　source　is　constrained　away　from　the　space　of　interference　sound　sources.　Finally,　the　covariance　matrix　of　interference　sound　source　plus　noise　is　estimated　based　on　the　estimated　steering　vector　for　obtaining　the　weights　of　the　MVDR　beamformer.　The　experimental　results　on　the　TIMIT　corpus　show　that　the　proposed　method　outperforms　the　reference　methods　on　the　tests　of　the　output　signal　to　interference-plus-noise　ratio　(SINR)　and　the　perceptual　evaluation　of　speech　quality　(PESQ)　and　has　a　better　performance　for　preventing　the　mismatch　of　the　steering　vector.　©　2023　Chinese　Institute　of　Electronics.　All　rights　reserved.