Through the pretreatment of 4, 4’-oxydianiline(ODA) with polyhydrogenmethylsiloxane (PHMS) using sodium hydroxide as a catalyst and subsequent reaction of this pretreated PHMS-ODA with 3, 3’, 4, 4’-benzophenonetetracarboxylic dianhydride(BTDA), polysiloxane can be attached to the polyamic acid by the silyl ester bond. By the thermal treatment of this polysiloxane-polyamic acid compound, well dispersed polymethylsilsesquinoxane (PMSQ) into polyimide can be obtained.