Abstract: Raffinose family oligosaccharides (RFOs) are 1, 6-galactosyl extensions of α-sucrose, and are plant non-structural carbohydrates, mainly including raffinose, stachyose and verbasose, which are commonly found in the plant kingdom middle. Among them, it is more common in legumes, Rehmannia glutinosa, Stachys japonica Miq., Stachys sieboldii and other plants, and belongs to functional oligosaccharides. RFOs have great potential in functional food development due to their active functions of regulating intestinal flora, preventing inflammatory bowel disease, protecting liver and lowering blood sugar. This article mainly reviews the sources of RFOs, the current research on the relevant technologies of extraction, separation and purification of RFOs, and the function of RFOs, expecting to provide some theoretical reference for the development and utilization of RFOs and enable them to be better applied in functional food.