Abstract: In order to enable people have a deeper understanding of the edible value of Ulva lactuca L,expand its consumer market,thus promoting the processing and high-value utilization of Ulva lactuca L. resources,the main nutritional components,amino acids composition content and parts of content of microelements in Ulva Lactuca L. were determined,then infrared spectroscopy method and HPLC method were used to analyze the composition of polysaccharide extracted from Ulva Lactuca L. The results showed that the contents of the protein,carbohydrate,crude fat,crude fiber and ash of the Ulva Lactuca L. were 22.03%,38.00%,8.77%,1.11%,30.09%,respectively. Ulva Lactuca L. was rich in human essential trace elements such as calcium,magnesium,iron. The amino acid varieties of the Ulva Lactuca L. were abundant,and the essential amino acids contents reached up to 5.9 g/100 g.Analysis of infrared spectrum and HPLC showed that the polysaccharide extracted from Ulva Lactuca L was mainly consisted of rhamnose(45.23%),xylose(26.04%),glucose(23.73%)and it contained ionic groups such as the uronic acid and the sulfonic acid.