This study was conducted to compare the differences of performance, nutritional quality and flavor compounds in beef of yaks, cattle-yaks and cattle. Yaks, cattle-yaks and cattle (13 heads per breed) with similar age, naturally farmed in Hainan state, Qinghai province were selected. Body measurements and slaughter performance were determined; the contents of regular nutritional components, amino acids and fatty acids were determined by national standard methods; the contents of inosine, inosinic acid and thiamine were determined by high performance liquid chromatography; and sodium glutamate content was determined by perchloric acid titration. The results showed as follows: 1) cattle-yaks showed extrusive hybrid vigor on body weight, body length, body high and bust circumference, as well as the weight before slaughter and the weight of head, skin, two fore hoofs, two hind hoofs, carcass weight, carcass meat and carcass bone. 2) Yaks and cattle-yaks had the characteristics of high protein and low fat; the beef of yaks and cattle-yaks was rich in amino acids; the content of polyunsaturated fatty acids in beef of cattle-yaks was significantly higher than that of yaks and cattle (P<0.05), and the content of monounsaturated fatty acids in beef of yaks and cattle-yaks was significantly higher than that in cattle (P<0.05). 3) Inosine content in beef of yaks was the highest, and was significantly higher than that of cattle (P<0.05); there was no significant difference in inosinic acid content among the three breeds (P>0.05); the content of thiamine in beef of cattle-yaks was significantly higher than that of cattle (P<0.05); the content of sodium glutamate content in beef of cattle and cattle-yaks was significantly higher than that of yaks (P<0.05). In conclusion, compared with yaks and cattle, cattle-yaks have extrusive hybrid vigor; the beef has the characteristics of high protein and low fat, and the contents of amino acids, unsaturated fatty acids and flavor substances are more rich.