Drying method of Pullulan polysaccharides

The invention relates to a drying method of Pullulan polysaccharides. The method comprises the following steps: preheating a Pullulan polysaccharide concentrate with the concentration of 5-15% to 60-70 DEG C by a plate heat exchanger, pumping the heated Pullulan polysaccharide concentrate to a pressure sprayer at the top of a drying tower by a high pressure homogeneous pump to form 40-55 [mu]m small liquid drops, mixing the small liquid drops with clean hot air, allowing small particles formed after drying to enter cyclone dust collection with discharged gas, returning the collected small particles to a tower top through wind, and allowing the small particles to collide with the small liquid drops and agglomerate in order to form a large particle material falling to a tower bottom fluidized bed; allowing the large particle material formed after drying to directly fall to the fluidized bed; drying the material falling to the fluidized bed through the fluidized bed, sending the dried material to a bag filter through wind, collecting the dried material, screening the collected material, and allowing the screened material to enter a finished product bin in order to obtain the Pullulan polysaccharide product with the bulk density of 0.15-0.35 g/ml. Spray drying and instant material drying in the invention make the contact time of the material with high temperature air extremely short and the product have high whiteness and good appearance, the spray dried product has a micro-porous structure, can be instantly dissolved in water and has small bulk density; and the method is simple, and is suitable for industrial large-scale production.