Abstract:Four banana cultivars in 1st-7thripening states were chosen as raw materials. They were Musa AAA Cavendish，Musa ABB Pisan Awak，Musa AA Pisang Mas and Musa ABB Bluggoe. The ultrasonic-assisted method was used to extract banana oligosaccharides and the oligosaccharide contents were determined. Sephadex G -25 column chromatography was used to separate and purify banana oligosaccharides. Results showed that the content of banana oligosaccharides of four varieties increased with the increasing maturity. Therefore bananas at the 7thripening state was the most suitable for extraction of oligosaccharides and bananas at the 1st-4thripening states was not suitable for oligosaccharides extraction. The higher content of banana oligosaccharides isolated from four banana cultivars was named oligosaccharides-I. In terms of physicochemical properties，all of oligosaccharides-I were pale yellow，odorless，insoluble in alcohol，ether. Three other oligosaccharides-I were flocculent，soluble in water，hygroscopic，except that Musa ABB Bluggoe oligosaccharides-I was powdery，partially insoluble in water，weak in hygroscopicity. The molecular weight of Musa AAA Cavendish，Musa ABB Pisan Awak and Musa AA Pisang Mas oligosaccharides-Ⅰmeasured by MS were 1 632.85 Da，1 693.24 Da and 1 746.44 Da.