The present invention provides an ionic polymer membrane prepared by irradiating the compound represented by formula 1 and an ionic polymer. The ionic polymer membrane of the present invention has the advantage of excellent processability, low production costs, high ion exchange capacity and high durability. Also, the method for preparing the ionic polymer membrane of the invention not only facilitates the production of the ionic polymer membrane in a 3-dimensional network structure which has high ion exchange capacity and high dimensional stability but also makes it easy to produce membranes in various forms and sizes by using the composition itself as a coating solution with using the commercialized inexpensive ionic polymer without additional high-risk multi-step introduction process of ionic exchange group. In the aspect of preparation process, the simplicity of the process and suitable for the mass-production, and the production cost is reduced by saving the processing time as much as minimum 1/15 (56 min.) in comparison to the processing time of the conventional thermal-crosslinking (1 hour).