Abstract: In order to scientifically evaluate the nutritional quality of fresh kelp, 19 kinds of main nutrients of 13 kinds of fresh kelps from Dalian, Xiapu and Rongcheng area had been researched. Based on the principal component analysis method, 19 kinds of main nutrients including dietary fiber, alginate, mannitol, iodine, glutamate, aspartic acid, glycine, alanine, serine, proline, methionine, magnesium, potassium, calcium, iron, zinc, manganese, phosphorus and sodium, had been compared and analyzed. The nutritional quality evaluation method of fresh kelp was established, and the nutrition quality of 13 kinds of fresh kelp was ordered. The results showed that there were significant differences in the nutritional quality among the fresh kelps. The coefficient of variation (CV) of iron, zinc, manganese and iodine were 97%, 66%, 66% and 58% respectively, and the CV of the remaining nutrients was more than 15%. There was certain correlation between some nutrients. In principal component analysis, 5 principal components were extracted, with a total cumulative contribution rate of 87.428%.The first principal component was highly connected with mannitol glycine and serine, determining the size of the second principal components wad mainly iodine, zinc and manganese. Magnesium and aspartic acid were an important contributor to the variance for the third principal component. Dietary fiber and alginate had the greatest contribution to the fourth principal component. The potassium and phosphorus elements had a large load on the fifth principal component, indicated that the contribution rate of mannitol, kelp polysaccharide, sweet amino acid, umami amino acid and mineral elements to the evaluation of Marine nutrient quality was higher, could be used as an important nutrients to assess the evaluation on kelp nutritive quality. Principal component analysis was quite suitable for the evaluation of nutritive quality of fresh kelp. On the basis of the comprehensive score, sample No.6 from Xiapu revealed excellent quality, followed by sample No. 13, sample No. 12 and sample No. 11 from Rongcheng.