Abstract: Measure mentsweremade on bioche mical components in muscles ofSilurus lanzhouensiswhich is an ende mic fish living in them iddle-up reach of theYellow R iver1Samples were collected fro m Hukou to Sanmenxia section of theYellow River in China during 2004) 20051M ain nutrient contents, am ino acids, fatty acids and main m ineral ele ment were ana-lyzed by using 6 groups and trace ele ment by 11 groups, wh ich from 4-individuals1Each groupwas composed of 3 ind ivid-uals1The results showed that contents of crude protein, crude fat, ash andmoisture of freshmusclewere (17.4?.7)%, (1.12?.09)%, (1.1?.09)% and (80.4+0.8)% respectively1The composition of a m ino acids ofmusclewas 18, a mong wh ich there were 8 essential amino acids for human needs1 In dry sample, the total content of a m ino acids was (71.29?.71)%; the content of essential amino acidswas (30.24?.18)%; 4 kinds of delicious a m ino acids accoun-ted for 24.62% 1Glu was themost abundant and Cyswas the shortest in all amino acids of themuscle1The percentage of essential amino acids in totalwas 42.38% 1The essential am ino acids index (EAA I) was 69.30 and the constitutional rate of essential amino acids accorded w ith FAO/WHO standard1A ccording to nutrition evaluation, in the am ino acids score (AAS) and che m ical score (CS), the lm i ited am ino acids ofS ilurus lanzhouensiswereVa,l Leu and Ile14 saturated fatty acids and 9 unsaturated fatty acidswere found in muscle and the amount of unsaturated fatty acidswas 651-10% 1C18B 1 and C18B-were themain unsaturated fatty acids, which was 411531% and 7.309% respectively1M inerals such as P, Na, K, Ca, Mg, Zn, Fe and Sewere rich in these sa mples1The content ofP was sign ificantly higher than othermineral ele-ments(p<0.05)1 In all elements, Zn was the richestm icroele ment, which was 10118mg/kg (fresh), Fe and Sewere sec-ondary and tertiarymicroel ment, respectively, which was 8131 mg/kg and 0131mg/kg1Furthermore, the ratio of Zn and Cu was not rationa,sowereZn and Fe1Our study indicated thatSilurus lanzhouensiswas one of the freshwater fishes with better nutritive value and raising value