In order to illustrate the physiological variation of different generations and different thallus parts of Saccharina japonica, physiological parameters such as maximum and effective PSII photochemical efficiency, nutrient uptake, and elemental composition were determined in the laboratory. Photosynthetic analysis in different generations indicated that, although gametophytes had higher pigment contents than the sporophyte, they had lower values of F v/F m and ΔF/F′m. The highest Chl a/Chl c ratio was found in sporophyte generation (3.98 ± 0.01) and in the basal part of fresh thallus (2.66 ± 0.02). The sporophyte had significantly higher values of nitrate uptake but lower values of phosphorus uptake than the gametophytes. The contents of nitrogen and carbon as well as C/N in gametophytes were significantly higher than those in sporophytes. In addition, the basal part of the S. japonica thallus had the highest C content (22.31 ± 1.50 %) but the lowest N content (2.02 ± 0.16 %), as well as the highest value of C/N (11.02 ± 0.34).