WAXD and SAXS were used to study the morphology structure of a new type polyether-polyester-polyurea cast elastomer.The WAXD result shows that the crystallinity in its hard segments is in the order of HDI M MDI M TDI by using three different diisocyanates.As for the mixd synthesis series of HDI and MDI

three phases morphology are formed due to the quite different reaction rates with "polamine".The SAXS result shows that the increasment of "polamine" molecular weight is favourable for the phase separation of soft and hard segments. For dif-ferent diisocyanates

the degree of phase separation is also in the order of HDI>MDI>TDI.