The fluidizing temperatures of gels from visual inspection were almost the same as the melting temperatures of gels from DSC. Therefore the gel formation was thought to arise from the crystallization of PEO in PEO/DMF solution. The composition dependence of gel melting temperature shows the same tendency as that of equilibrium melting temperature. which cleans that the variation of gel melting temperature with composition comes from the thermodynamic interaction between PEO and DMF. The values of Avrami exponent. kinetic rate constant and the reciprocal of crystallization half time wore determined as a function of PEO concentration and the degree of supercooling. The crystallization rate increased with the degree of supercooling and PEO concentration in PEO/DMF solution.