Abstract:The effects of vacuum drying，hot air drying，flat drying and vacuum freeze drying on the physicochemical properties and in vitro hypoglycemic activity of Hylocereus undatus stem polysaccharides were studied.The four drying methods had significant effects the on the pitaya stem polysaccharides.The highest yield of pitaya stem polysaccharides treated by vacuum freeze drying was（19.75±0.21）%.The four drying methods significantly affected the water and oil holding capacity of the pitaya stem polysaccharides （P＜0.05）.The pitaya stem polysaccharides after vacuum freeze drying and hot air drying had higher water and oil holding capacities than those after other methods.In vitro antioxidant and functional activity experiments showed that the freezedried pitaya stem stem polysaccharide had a better ability to scavenge DPPH·，·OH，as well as good glucose binding ability and α-amylase activity inhibitory activity.Among the drying methods，freeze drying is better to obtain high quality and high activity pitaya stem polysaccharides.