This paper reports the influenee of two different feeding ways in preparation of segmented polyether ureihane (SPEU) by a two-step method on dynamic mechanical Properties of SPEU．Experimental results indicate that (1) when chemical composition and nlolar ratio of reactants were kept unchanged，the extent of microphase separation in SPEU was affected by the feeding ways．The extent of mierophase separation of bulk SPEU polymer Prepared by the first reaction feeding way，i．e．[PTMEG—DMI]—Extender，is better than that obtained by the seeond reaction feeding way，[PTMEG—MDI] —Extender．(2) The effect of reaction feeding ways on dynamic mechanical properties of the SPEUS is more evident in 1

4-butanediol (BDO) extending samples．(3) The samples extended with 1

2-ethylenediamine have better phase separation that the samples extended with BDO．