Coalition　formation　is　a　key　topic　in　multiagent　systems.　How　to　do　a　further　search　after　the　lowest　two　levels　of　the　coalition　structure　graph　is　a　problem　which　hasn＇t　been　resoled　for　a　long　time.　The　paper　analyzes　the　relations　among　cardinality　structures　deeply　and　presents　an　algorithm　to　improve　the　current　best　one　of　Shexiong　Su　and　Shanli　Hu　et　al＇s.　It　not　only　perfects　its　solution　of　for　the　case　m　≥　h　and　analyzes　how　to　do　away　with　some　redundant　search　to　decrease　the　demanded　searching　number　further,　and　gives　the　proof　of　the　related　result.　©　2009　IEEE.