Longan polysaccharide (LP) was extracted from longan (Dimocarpus longan Lour.) pulp. The composition and rheological properties were determined by chemical analysis and dynamic shear rheometer. The flow behavior and viscoelastic behavior of longan polysaccharide (LP) solution were investigated by steady shear and small amplitude oscillatory shear (SAOS) experiments, respectively. The result shows that the solution is a pseudoplastic flow in a range of shear rate (1-100 s-1). The rheological behavior of LP was influenced by cations such as Na+ and Ca2+. With an increase of apparent viscosity, G′ and G′′ were accompanied by addition of Na+ and Ca2+.