Sodic soil is more likely to deteriorate in paddy fields than in other fields. Flue gas desulfurization (FGD) gypsum can reclaim sodic soils, but how long a one-time application of FGD gypsum provides benefits in paddy fields is poorly understood. In this study, soil salinity, sodicity, and soluble and exchangeable cation concentrations were evaluated over a 7-year period to investigate the reclamation of sodic soil in a paddy field by FGD gypsum. After 7 years, compared with those in the initial soil, the pH, sodium adsorption ratio, and exchangeable sodium percentage of the topsoil (0-20 cm) decreased by at least 2 units, 72.2% and 80.9%, respectively. In the process of FGD gypsum reclamation, substantial changes in topsoil salinity and sodicity