With the development of large-mouth bass, Micropterus salmoides cultivation, artificial feed have become the key of increasing feed efficiency. The objective of this study is to determine the effects of dietary protein, fibre and fat on the growth of large-mouth bass. Accornding to orthogonalty trial Table L9(34), using casein, cellulose and soybean oil, the feeding tests were carried out for 23-29g young fish. The content of components was designed 3 levels: protein of 39%, 42%, 45%; fiber of 2. 5%, 3. 5%,4. 5%; fat of 5%, 6% and 7%. The results show that protein and fiber had signficant differences on weight gain among their levels (P<0. 05), i. e., 42% and 45% protein were better than 39%; 2. 5% and 3. 5% fiber were better than 4. 5%. Protein efficiency ratio apparent digestibility and food coefficient ratio showed further that 42% protein and 2. 5 % fiber were the best. There was no difference on weight gain and protein efficiency ratio among fat levels (P>0. 1), 5%-7% fat is also the suitable content. Thus the large-mouth bass's best compounded diet suggested is 42% protein, 2. 5 % fiber and 6% fat.