Solar　cavity　receiver　is　quite　often　utilized　in　the　solar　tower　power　system.　It　is　a　photo-thermal　conversion　component,　which　absorbs　solar　radiation　energy　and　heats　the　working　fluid.　The　safety　and　thermal　efficiency　of　solar　cavity　receiver　can　directly　affect　the　efficiency　of　the　entire　power　system.　In　this　paper,　a　modified　combined　method　is　proposed　to　simulate　the　thermal　performance　of　a　saturated　water/steam　solar　cavity　receiver.　Compared　with　the　combined　method　presented　previously,　this　modified　one　can　describe　the　whole　steady　process　of　the　receiver　and　accurately　estimate　the　steady-state　efficiency　and　the　mass　flow　rate　of　the　generated　steam　in　the　boiling　tubes.　Under　the　given　boundary　condition　of　incident　solar　flux,　the　modified　method　is　adopted　to　find　an　optimized　distribution　of　absorptivity　in　the　solar　wavelength　band　for　the　absorber　surfaces　in　order　to　improve　the　uniformity　of　surface　heat　flux　distribution.　The　simulation　results　show　that　the　uniformity　of　surface　heat　flux　is　improved　effectively　and　the　maximum　mean　square　deviation　of　the　external　tube　temperature　drops　from　32.4　degrees　C　to　23.6　degrees　C　after　optimizing.　Based　on　the　relatively　uniform　heat　flux　distribution,　the　effect　of　thermal　emissivity　of　the　absorber　surfaces　on　the　thermal　performance　of　the　cavity　receiver　is　further　investigated.　Being　different　from　those　of　parabolic　trough　and　external　cylindrical　receivers,　both　the　radiative　and　the　convective　heat　loss　of　the　present　cavity　receiver　decrease　with　increasing　thermal　emissivity,　which　improves　the　receiver＇s　efficiency.　These　results　can　provide　a　useful　reference　for　the　design　and　selection　of　surface　coatings　for　the　cavity　receivers.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.