Abstract: A series of segmented polyether urethanes (SPEU) were synthesized from 4, 4-diphenylemthane diisocyanate (MDI), polytetramethylene glycol (PTMG) and low molecular weight diols as the chain extender by the two-step solution polymerization with a mixture of dimethyl sulfoxide (DMSO) and methyl isobutyl ketone (MIBK) as the solvent. The effect of the reaction temperature on the intrinsic viscosity of the SPEU was studied. There was a slight change in viscosity of the polymers in the reaction temperature range of 60~110℃. The high molecular weight polymers without crosslinking were obtained by using a lower reaction temperature (at about 60℃). The effects of the structure and amount of the chain extender on the mechanical properties of the SPEU were discussed. Some of them can be used in the balloon of the Intra Aortic Balloon Pump (IABP) which exhibited excellent mechanical properties and blood compatibility.