Abstract: In order to explore the nutritional composition, mineral element contents, and the intrinsic relationship among the indicators in different macroalgae, the nutritional components and main mineral elements of five artificially cultivated macroalgae including Pyropia haitanensis, Pyropia yezoensis, Gracilariopsis lemaneiformis, Saccharina japonica and Undaria pinnatifida were determined, and the principal component analysis (PCA) was used for the comprehensive evaluation. The results showed that the total carbohydrate content of Saccharina japonica was as high as 69.65%, the crude protein content of Pyropia yezoensis was 45.47%, and the crude fat and ash content of Undaria pinnatifida were also higher than those of other species. The ability of brown algae (Saccharina japonica and Undaria pinnatifida) to enrich calcium (Ca), potassium (K), and sodium (Na) was higher than that of red algae, but the red algae (Pyropia haitanensis and Pyropia yezoensis) exhibited significantly higher enrichment of phosphorus (P), while their enrichment of iron (Fe) and magnesium (Mg) varied with the species of red algae. The correlation analysis showed that carbohydrate content was significantly negatively correlated with the protein-related indicators; Ca content was extremely significantly positively correlated with K and Na contents; and Fe content was extremely significantly negatively correlated with Ca and K contents, as well as ash content with protein-related indicators. The further principal component analysis revealed the differences in the characteristics of the five macroalgae in the three core dimensions of nutritional composition (carbohydrate and protein trade-off), mineral metabolism, and trace elements and fiber variation through three principal component axes (PC1, PC2, and PC3) with the cumulative contribution rate of 92.87%. In summary, the contents of nutrients and mineral elements in the five macroalgae showed obvious species specificity and a carbon-nitrogen metabolic trade-off characteristic. This result could provide guidance for the high-value utilization of macroalgal resources.