he influences of different level of ionization on the morphology of the ionic aggregates in the block polyurethane anionomer were studedby the small angle X-ray scattering in this paper. The results indicated that it would mainly exist in the form of nonclustered ions or multiplets at lesser ion contents while in the form of clusters at higher ion contents. The ionization of the polyurethane is in favor of the microphase separation of the soft and hard segments.