Polydimethylsiloxane (PDMS) is the typical material for catheter, although the excellent biocompatibility of PDMS, PDMS has some problems such as difficulty in coating and operability. We consider the introduction of an aromatic ring with sulfobetaine substituents into the main chain of PDMS to solve the problems. Poly (tetramethylsilphenylenesiloxane)(PTMS) is the representative polymer where an aromatic moiety is incorporated into the polysiloxane backbone, which would presumably improve the good properties of polysiloxane, especially the thermostability. It has been reported that the properties of poly(tetramethylsilarylenesiloxane) derivatives depend on the kind of arylene moiety, the substituted position of dimethylsilyl groups as well as the substituent, on the arylene moiety. Therefore, we examined the synthesis and physical properties of the multi-block copolymer based on polysiloxane with sulfobetaine substituents.