The invention discloses a method of processing Zingiber zerumbet for producing a processed sample of Zingiber zerumbet, which easily releases flavonoids in a following extraction process. The method includes the steps of: soaking a raw sample of Zingiber zerumbet with a processing reagent selected from rice vinegar or yellow wine at 23-27° C. for 20-28 hours and steaming the soaked product at 0.6-1.4 kg/cm2, 80-120° C. for 20-40 minutes.