The invention provides a production method of a cation exchange alloy film. The production method comprises the following steps: firstly, mixing thermoplastic polyethylene-sulfonated polystyrene strongly acidic cation exchange resin powder, non-thermoplastic micron-grade weakly acidic cation exchange resin powder (or non-thermoplastic micron-grade weakly alkaline anion exchange resin powder), polyethylene powder and polyisobutene powder; then carrying out internal mixing, open mixing and sheeting, continuous calendering, cooling and cutting to obtain a single prefabricated film sheet; finally,clamping one piece of enhanced mesh cloth by utilizing two pieces of the prefabricated film sheets; carrying out hot pressing to obtain a cation exchange alloy film product. The film has a smooth surface and a strong anti-pollution capability; a thermoplastic component and a non-thermoplastic component form a starry-sky-type high molecular alloy structure and the resistance of the film is low; the enhanced mesh cloth limits the swelling of the film in a strongly acidic or strongly alkaline solution and an inner structure is dense. The cation exchange alloy film provided by the invention is especially suitable for electroosmosis application occasions under a strongly acidic or strongly alkaline solution environment.