Bread staling is a deterioration process that causes serious economic losses in the food industry. The objective of this research was to determine the impact of Laminaria japonica polysaccharides (LJP) on the anti-staling properties during storage. The baking, thermal, starch retrogradation, and microstructure properties of bread with LJP during room storage were investigated. The results showed that the addition of LJP improved specific volume and textural properties. The kinetic model showed that the addition of LJP decreased the rate constant. Meanwhile, LJP addition exhibited a significant decrease of enthalpy and crystallization in the frozen dough bread. Data also showed that LJP may form more hydrogen bonds and interfere the starch reassociation and retrogradation. This effect was also evident in the microstructure, showing that LJP could improve the fresh quality and delay the deterioration of the bread structure. Overall, LJP can potentially be used as an effective natural additive to increase the storage stability of baked food.