Abstract: The purpose of the research is to study the relationship between the content of soluble protein and the free amino acids during the germination of tobacco seeds. Using both flue-cured tobacco K326 seed and burley tobacco TN86 seed as the studying materials, the content of soluble protein and the free amino acids in tobacco seed was tested by ultraviolet and visible light spectrophotometer. In this article, when tobacco seeds germinated, the dynamic changes of content of soluble protein and the free amino acids were concerned with the changes of such components at 0h, 2h, 6h, 12h, 18h, 24h, 30h, 36h, 42h, 48h, 60h, 72h, 84h, 96h, 168h, 336h, respectively. The results showed that the contents of the soluble protein in flue-cured tobacco K326 seed reached its maximum value at the 96th hour, while it was at the 168th hour in burley tobacco TN86 seed. The maximum value at the 336th hour so did the contents of the free amino acids in both flue-cured tobacco K326 seed and burley tobacco TN86 seed during the germination of tobacco seeds. The dynamic changes between the contents of the soluble protein and the contents of the free amino acids presented the very notably positive correlation.