Abstract: In order to investigate the utilization potentials of tobacco (Nicotiana spp.) seeds, the seeds of 6 varieties of N. rustica L.and 31 varieties of N. tabacum L. were collected to study the difference in the composition and contents of crude protein, fat, fatty acid, phytosterol and squalene among varieties with an one-way analysis of variance (ANOVA) method. The seeds of N. rustica varieties contain higher crude protein and lower fat comparing to those of N. tabacum varieties. The contents of crude protein and fat were significantly different among the seeds of N. tabacum varieties. The seeds of N. rustica varieties have higher content of Met, Lys and total essential amino acids than those of N.tabacum, and also have a higher ratio of essential amino acid to non-essential amino acid as well as a higher ratio coefficient of amino acids. The amino acid pattern in N. rustica varieties is close to the FAO/WHO recommendation and has a high closeness coefficient with eggs protein recommended by FAO. The contents of linoleic acid, campesterol and β-sitosterol were obviously higher in the seeds of N. rustica varieties than in those of N. tabacum varieties, which showed an opposite pattern to the contents of squalene, cholesterol, 4-methyl-7-encholestyl alcohol, stigmasterol and α-sitosterol. There was no significant difference in the contents of total unsaturated fatty acid and sterol between the seeds of N. tabacum varieties and N. rustica varieties. In conclusion, the seeds of N. rustica have a higher feed value while the seeds of N. tabacum have a higher fat value.