Transition metal ions, such as Ag+, can form complexes with olefins. In the present work, a cation exchange membrane loaded with an ionic liquid was prepared for the separation of olefin/paraffin by electrodialysis based on the complexing between olefins and Ag+. The effects of Ag+ concentration and current intensity on the separation efficiency were investigated. Experimental results indicate that, the introduction of choline lysine ionic liquid ([Ch] [Lys]) to the cation exchange membrane significantly improved the olefin/paraffin separation efficiency. The Ag+ concentration and current intensity were optimized to be 1 mol/L and 0.002 A, respectively, which gave the separation selectivity to 1-hexene/n-hexane up to 9.5 and the permeation flux of 1-hexene up to 11.6 mL/cm(2).h.