The melting behavior of hydrated polyacrylonitrile (PAN) and the rheological properties of hydrated PAN melt were investigated using DSC md modified capillary rheometer. With increasing the water content, Tm of the hydrated PAN was rapidly decreased and finally levelled off above a critical water content. However, the melt viscosity was further decreased even above the critical water content. The hydrated PAN melt showed a typical shear thinning behavior. In arrhenius plot, when the hydrated PAN melt was supercooled, it exhibited a different dependency on temperature from that above melting temperature.