To improve the dimensional stability of electrodialysis membranes, a series of crosslinked sulphonated polysulfone cation exchange membranes with different degrees of sulfonation were prepared by a simple and low energy consumption method, namely UV-crosslinking. The crosslinking reaction was performed by UV irradiation and using 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (TPO) as photoinitiator and trimethylolpropane tri-acrylate (TMPTA) as crosslinker. The scanning electron microscopy (SEM) and atomic force microscopy (AFM) results showed that crosslinking leads to a denser and smoother surface. Compared with the swelling and water uptake results of pristine membranes, the crosslinked membranes exhibited an enhanced dimensional stability, especially at higher temperature (40-70 degrees C). The thermogravimetric analysis and measurement of mechanical properties indicated that the crosslinked membrane has better mechanical and thermal properties. The electrochemical properties were analyzed, and the membrane after crosslinking showed a better ion permselectivity. When applied in electrodialysis and compared to the commercial membrane with a NaCl removal ratio of 75.6%, the crosslinked membranes showed a more efficient performance (NaCl removal ratio = 89.1% for SPSU-60). These improvements showed that the crosslinked membranes can be promising candidates for high-temperature and industrial application.