The　reconstructed　amplitude　distribution　of　digital　holography　suffers　from　the　contamination　of　speckle　noise.　We　introduced　and　demonstrated　an　approach　using　phase　SLM　(spatial　light　modulator)　to　reduce　speckle　noise　in　digital　holography.　Multiple　holograms　were　recorded　through　different　illumination　angle　via　SLM　modulation.　The　speckle　noise　in　the　reconstructed　image　is　suppressed　by　averaging　these　fields.　The　modulation　interval　of　SLM　exceeds　the　minimum　angle　of　uncorrelated　speckle　pattern.　Both　reflective　and　transmissive　experiments　were　conducted　using　USAF　test　target　as　the　sample.　The　results　show　that　the　speckle　noise　was　obviously　suppressed　and　the　contrast　dropped　to　36%　of　the　initial　value　using　25　different　angles.　With　the　help　of　SLM　modulation　of　illumination　angle,　the　operation　speed,　accuracy　and　stability　of　the　experiment　has　been　greatly　improved.