Copolymerization of acrylonitrile (AN) with hydrophilic monomers is one of the research directions in the preparation of fouling-resistant polymeric materials. In this study, poly(acrylonitrile-co-maleic acid) copolymer (P(AN-co-MA)) membranes were prepared by ⁶⁰Co γ-ray-induced copolymerization of AN and MA in a dimethyl sulfoxide (DMSO)/water mixed solvent. A phase inversion method was then applied. The effects of the solvent on the monomer conversion and molecular weight of the copolymer were investigated. The dependence of porosity, hydrophilicity, Zeta potential, and anti-fouling properties of the copolymer membranes on the molar feed ratio of maleic anhydride (MAH) was also studied. The results showed that in the DMSO/water mixed solvent under a mass ratio of 3∶2, the monomer conversion rate could reach over 80%, and the molecular weight of the obtained copolymer was close to 220 000. The porosity and hydrophilicity of the copolymer membrane increased with an increase in the molar feed ratio of MAH. The adsorption capacity of the copolymer membrane under a molar feed ratio of MAH of 30% for bovine serum albumin was only 52.1% of that of the polyacrylonitrile (PAN) homopolymer membrane. This study provides a useful reference for preparing PAN-based anti-fouling membranes with a controllable structure and properties using a radiation technique.