Sulfonated poly(arylene ether ketone ketone sulfone)s (SPAEKKS) copolymers were prepared by aromatic nucleophilic polycondensation. The SPAEKKS membranes were characterization using FT-IR, DSC, TGA and TEM. The water uptake, IEC, transport parameters (H+, Na+ and K+), oxidative and thermal stability and mechanical strength of membranes were comprehensively investigated. This study found that the SPAEKKS-4 showed a good combination of the ion diffusion coefficient (DH+ : 1.01 x 10(-10); DNa+ : 5.85 x 10(-11); DK+: 1.68 x 10(-11)), excellent mechanical strength (tensile strength: 55.3MPa; tensile modulus: 1.74 GPa), acceptable water uptake (26-54 wt%), favourable oxidative stability (oxidative stability time reached 29 h) and good thermal properties (T-g above 300 degrees C, T-d5% above 270 degrees C). It suggested that the SPAEKKS membrane was promising for possible use as an ion exchange membrane.