In　this　paper,　a　method　to　simulate　the　absorbing　effectiveness　of　spherical　particle　absorber　is　presented　and　the　effect　of　the　diameter　of　spheres,　the　number　of　layer　and　the　stack　modes　of　sphere　particle　to　the　absorbing　effectiveness　were　also　researched.　Basing　on　the　simulation　results,　an　optimal　spherical　particle　absorber　was　designed.　The　absorber　has　3　layers　with　I　mm,　2　mm　and　4　mm　spheres　stacked　on　each　layer　respectively.　Simulation　result　shows　that　the　optimal　absorber　achieves　a　maximum　reflection　loss　of　-15　dB　and　the　bandwidth　being　lower　than　-5　dB　is　more　than　16　GHz　in　1　similar　to　18　GHz.