Abstract: In order to promote its comprehensive development and utilization of Silybum Marianum, the content of protein, fat, starch and mineral element were determined, and the amino acid and fatty acid composition were analyzed to systematically dectet and evaluate the nutritional composition. The results showed that the protein content of Silybum marianum seeds was 12.05%, and the variety of amino acids was abundance which included 7 kinds of essential amino acids（tryptophan not detected）. The ratio of essential amino acids to total amino acids（EAA/TAA） was 0.324 0, and the SRC was 73.3, as well as containing high nutritional value. Leucine was the first limiting amino acid. The starch content of silybum marianum seeds was 227.25 mg·g^-1. The variety of mineral elements was abundance, including calcium, magnesium, potassium, iron, zinc, manganese, selenium and other beneficial mineral elements, and the order of content was calcium＞ potassium＞ magnesium＞ phosphorus＞ iron＞ sodium＞ aluminum＞ zinc＞ copper= manganese＞ molybdenum＞ nickel＞ boron＞ selenium. The crude fat content of silybum marianum seeds was 31.74%, which was rich in 29 types of fatty acids, including 11 unsaturated fatty acids, accounting for 66.12%, and had a high proportion of unsaturated fatty acids. The nutritional value of Silybum marianum seeds was very rich to be used as a potential source of protein, fatty acids and starch. To sum up, it can be processed and utilized in both medicinal and non medicinal parts, with huge development potential.