β-glucan has a variety of physiological activities and good physiological functions. Dictyophora indusiata (Vent. Pers.) Fisch. contains lots of β-glucan， while its structure and solution properties are not understood clearly. In this paper， a water-soluble polysaccharide (DIPP) was extracted from D. indusiata. The physicochemical properties， structure and solution properties of DIPP were characterized by acid hydrolysis， infrared spectrum， methylation， scanning electron microscope (SEM)， high performance size exclusion chromatography multiangle laser light scattering (HPSEC-MALLS) and rheometer. The results showed that the weight average molecular mass of DIPP was 2.8×106 u， and only glucose was detected. The sugar residues were T-Glap (29.8%)， 1，3-Glcp (42.6%) and 1，3，6-Glcp (27.8%). The infrared spectrum showed that DIPP contained β-configuration. In dilute solution， DIPP had high intrinsic viscosity ([η]=1 094.3 mL/g). The DIPP solution (0.5%) showed high viscosity and gel properties. In conclusion， DIPP is a β-glucan with high viscosity. The results of this study can provide structure basis for the polysaccharide functional activity research and product development.