The invention provides a method for preserving mulberry fruits with a coating film prepared from essential oil of three types of ginger. Multiple substances including Kacmpferia galangal essential oil, galangal essential oil, fresh ginger essential oil, chitosan and the like with antimicrobial activity are taken as a preservative. The method comprises steps as follows: fruit selection, disinfection, primary air drying, coating, secondary air drying and packaging. The multiple substances such as Kacmpferia galangal essential oil, galangal essential oil, fresh ginger essential oil, chitosan and the like with antimicrobial activity are integrated, the film prepared by compounding essential oil of three types of ginger and chitosan has a remarkable preservation function on mulberry fruits during postharvest storage, the postharvest taste and flavor change of the mulberry fruits can be significantly delayed, the breathing peak can be postponed, and increase of the malondialdehyde content and rise of the relative electrical conductivity and the activity of polyphenol oxidase can be notably inhibited, so that the preservation time is greatly prolonged. The method is simple, convenient, lower in cost and easy to popularize, and materials are easy to obtain.