Abstract: Polarizing microscope was used to observe the process of PEO10 W、PEO2 W and its blend isothermal crystallization process and crystal morphology of different temperatures.The result shows that under the same temperature,high molecular weight poly （ethylene glycol）had the fastest crystallization rates,and low molecular weight poly （ethylene glycol）had the lowest rates.For the blends,both crystal growth rates and nucleated rates are between their two pure components.Higher temperature is good for the growth of better crystal.