High　degree　of　uncertainty　in　wafers　cycle　time　brings　semiconductor　manufacturers＇　difficulty　in　making　feasible　order　promise.　After　analyzing　the　roots　of　deficiencies　in　conventional　order　promising　method,　we　develop　a　method　called　CRMPO　(Capacity　Reserved　for　Multi-Priority　Orders)　to　promise　orders.　By　dividing　all　orders　into　several　priorities　and　reserving　capacities　for　each　priority　in　advance,　CRMPO　can　improve　feasibility　of　order　promise,　satisfy　important　customers＇　orders　requirement　and　smooth　production　planning.　Finally,　we　investigate　some　critical　techniques　used　to　implement　CRMPO.　©　2010　IEEE.