Two novel polyphenylquinoxalines，PPQ-I and PPQ-II，containing benzofuran ring in the main chain were prepared by the reactions of 2-P (P’-chlorophenylglyoxalyl)phenyl-5-(P-chlorophenylglyoxalyl) benzofuran or 2-(P-phenylglyoxalyl) phenyl-5-phenylglyoxalyl benzofuran，which were synthesized in our previous work，with 3，3’，4，4’-tetraaminodiphenyl ether，respectivdy．Properties of the polymers in the form of segmental film were charac-terized bv TGA，DSC，tensile strength，elemental analysis and IR spectroscopy．Experimental results showed that the polymers exhibited good thermo—oxidative stability and tensile strength at room temperature．Decomposition temperatures of the polymers were all above 500℃ according to the TGA results．The tensile strengths were higher than 1000 kg／cm2 and the Tg values were greater than that of the PPQ without any benzofuran ring in the molecular structure．It was found that the polymers can be used as membrane materials．Hence the ultrafiltration (UF) membranes prepared from the polymers by a phase inver-sion method are also reported in this paper．The retention character of PPQ—I and PPQ—II UF membrane may be quantitatively determined by ball standard matter，such as Bovine seruln albumin (BSA) and Chymotrypsinum (CMP)．Due to the fact that PPQ—I obtained by using 2-P(P’-chlorophenylglyoxalyl) Phenyl-5-(P—chlorophenylglyoxalyl) benzofuran as one of monomers contains not only benzofuran ring in the main chain but also chloro—atom in the side chain，the flux of UF membrane made from PPQ—I is higher than that of PPO—II．The morphological structures of section of PPQ—I UF membrane have been observed bv SEM．