Abstract: In order to evaluate the inter-substitution among tobacco leaves, nine chemical components, including total sugar, total alkaloids, total nitrogen, cellulose, starch, polyphenols, ash, petrol-ether extract and total volatile bases, in 2482 flue-cured tobacco leaf samples belonging in 80 categories were determined, then the data were divided into 80 object sets and 30 validation sets, the approximate T² test values between the two data sets were calculated, and the inter-substitution among the leaves was evaluated by the ratio of T² to c², where c² was the critical values at a given confidence level. The results showed that:1)Chlorine was not applicable to be included in T² test, because the determined chlorine contents in a number of samples were not conformed to a normal distribution. 2)In the two data sets, the samples were of higher inter-substitution (T²/c²<1)if they were of the same grown area, grade and variety, while the samples were of lower inter-substitution (T²/c²>1)if they were of different properties. It was concluded that this method features higher accuracy and recognition ability and is applicable to the evaluation of inter-substitution among tobacco leaves.