The effects of aging temperature and weight usage of calcium-ammonia catalyst on the polymerization reaction of ethylene oxide for to polyethylene oxide (abbr. as PEO) synthesis wasere investigated. It showed that the aging temperature did not influenced the catalytic yield of PEO littleobviously, but determined the stability of polymerization significantly. Herewhich the stability of polymerization was measured by the variable coefficient of molecular weight of synthesized PEO products on the catalysts prepared at prepared at the same conditions. It exhibited a volcano shape with increasing the aging temperature, and Comparatively, the catalyst aged at 60℃ seemed was most stable, on in which the variable coefficient of molecular weight of PEO can be decreased to 7.3%, as well as the yield of PEO maintained at higher more than 99%. Furthermore, a series of PEO samples with a meanthe molecular weight of PEOs from 4.03.9 ×105 g/mol to 8.6 ×105 g/mol can be was synthesized controllably by changing the catalyst usage. Moreover, Bby characterizations of SEM, XRD and DCS, it was testified that the synthesized PEO was one kind ofpresented a kind of layered and partially crystallized polymers, and the crystalline degree increased with increasing the molecular weight of PEO.