Abstract: In order to systematically compare the quality of Ulva prolifera in different sea areas of China,the contents of dietary fiber,polysaccharide,protein,amino acid,fatty acid,mineral elements,ash,harmful element in Ulva prolifera were analyzed by routine physical and chemical methods,and the differences of various components were compared by SPSS. The results showed that the functional and harmful components of Ulva prolifera from different sea areas had great difference. The highest content of total dietary fiber,water-soluble dietary fiber and water-soluble polysaccharide in Ulva prolifera from Qingdao in Shandong were 49.33%,22.03% and 16.92%,respectively. The highest content of crude protein in Ulva prolifera from Yancheng in Jiangsu was 38.70%. The amino acid composition of Ulva prolifera from Nantong in Jiangsu was the closest to the ideal protein pattern. The highest content of savory amino acid in Ulva prolifera from Qingdao in Shandong was 90.53 g/kg. The EPA content in Ulva prolifera from Ningbo in Zhejiang was the highest,accounting for 1.19% of total fatty acids. The highest content of iron in Ulva prolifera from Qingdao in Shandong was 4967.41 mg/kg. The highest content of acid-insoluble ash in Ulva prolifera from Nantong in Jiangsu was 5.66%. Except for mercury,the contents of arsenic,lead,cadmium and chromium in Ulva prolifera from different sea areas exceed the maximum allowable limits of algae products and health food. Among them,the contents of harmful elements in Ulva prolifera in Qingdao were relatively low. This experiment can provide a more detailed theoretical basis for further research and development of Ulva prolifera resources.