In the present paper a new type of polyether polyester block copolymer (MPEE) consisting of two components of polyethers (PTMG and PEG) as soft segment component has been synthesized. And it has been also investigated in comparison with blended polyether polyester block copolymer (BPEE) consisting of the same composition ratio of hard and soft segments and both two polyethers (PTMG and PEG)

It was found that: (1) Improvement of blood compatibility of polyether polyester block copolymer can be achieved by in-troducing hydrophilic component PEG into it; (2) Generally the blood compatibility of MPEE type is better than that of BPEE; (3) Under a specific molar ratio of PTMGT-PET to PEGT-PET (60/40) the blended copolymer (BPEE 60/40) shows the best blood compatibility

as well as mechanical property. This might be related to more tiny microphaseseparted structure. The relationship between blood compatibility and structure of copolymer has been discussed.