A new kind of non-ionic salt and temperature resistant biopolysaccharide polymer, dextran, was produced by Sclerotium Gum. Scleroglucah is a kind of natural capsule polysaccharide. The solution of hard dextran has a special stability at high temperature, a good applicability in a wide range of pH value, a great tolerance for a variety of electrolytes in the presence of solution, a high degree of pseudoplasticity of the solution, and a little change in the viscosity of the solution caused by temperature rise and fall.