In this study, polyketone was graft copolymerized with sodium styrene sulfonate(SSS) using ⁶⁰Co γ-ray irradiation. Structure of the membrane was confirmed by Fourier-transform infrared (FTIR) spectroscopy. The water uptake(W.U), ion exchange capacity(IEC), and electrical resistance(E.R) of the membrane were measured to evaluate the electrochemical properties of prepared membranes. The grafting rate of the polyketone-g-sodium styrene sulfonate cation exchange membrane increased from 14.4% to 81.4% as the irradiation dose and the SSS concentration increased. The swelling ratio ranged from 7.9% to 34.2%. The ion-exchange capacity was 0.43 meq/g to 1.1 meq/g and the electrical resistance was 12.2 Ω·cm2~2.1 Ω·㎠, which decreased as the ion-exchange capacity increased.