The Partial Least Square Regression (PLSR) analysis was used to study the specific influence of free and hydrolyzed amino acids contents on sensory quality of 10 different kinds of commercial tobacco. The results showed that there were negative correlation between free amino acids and most of sensory quality. Asp, his and thr of the free amino acids have the most significant influence on comfort characteristics. Thr, glu and his of the free amino acids have the most significant influence on smoke characteristics. It indicates that the lower tobacco free amino acids contents, the higher sensory quality. Hydrolyzed amino acids have less influence on sensory quality of cigarettes than free amino acids.