Disclosed is a preparation process for an ion exchange membrane. The preparation process comprises the following steps of S1, weighing nano zinc oxide modified high-density polyethylene, polyisobutene, a coupling agent, a visible light initiator and a cross-linking agent and then pouring the components into a high-speed mixing agitator to be uniformly mixed at a normal temperature, then adding negative ions/negative ion resin powder based on proportion; S2, pre-fabricating a sheet material from the mixture in the step S1, and enabling macromolecule material net cloth to be adhered to the two sides of the sheet material; S3, putting the sheet material with the macromolecule material net cloth into a multi-layered electric heating template, and heating, pressing and shaping the sheet material at a temperature of 180-220 DEG C for 1.0-2.5h; and S4, after the sheet material obtained in the step S3 is heated, cooling and sizing the sheet material, and finally taking the sheet material out of the die. By adoption of the preparation method, the efficient ion exchange membrane with the exchange capacity of about 4.6mol/kg and the membrane surface resistance of about 5.02.cm<2> can be obtained; and in addition, the ion exchange membrane is suitable for deep desalination of industrial pure water, so that the ion exchange membrane can be widely applied.