The invention discloses a compound enzyme preparation and an extraction method for improving an extraction rate of banana polyphenols. The compound enzyme preparation is prepared from the following components in parts by mass: 10-20 parts of amylase, 1-5 parts of protease, and 30-50 parts of a banana oxysporum enzymolysis agent; the banana oxysporum enzymolysis agent is prepared through the following methods that raw banana skin is dried, ground into powder, and mixed with bran, water is added until the mixture with the moisture content over 25%, banana oxysporum is added and cultured for 10-24 d, and precipitation and filtering are conducted to obtain a filtrate; and chitosan and zeolite are mixed with the filtrate, and the obtained mixture is stirred for 20-30 min at 100-200r/min, and dried at the room temperature for pelletizing to obtain the banana oxysporum enzymolysis agent. According to the method, through the compound enzyme preparation, degradation is conducted; enzyme, the zeolite and ultrasonic assist enzymolysis to fully degrade and break banana so that polyphenols is extracted through precipitation, and the membrane filtration method is used for removing impurities with the high extracting rate and purity.