Abstract: In order to find out the relationship between chemical components and equilibrium moisture content, the chemical components (carbohydrates, reducing sugars, total alkaloids, chlorine, potassium, starch, total nitrogen, petroleum ether extracts and proteins) in and equilibrium moisture content of 63 flue-cured tobacco samples from different areas were determined. Principal component analysis (PCA) was adopted to convert the chemical components with colinearity into two independent principal components, and the correlation analysis between principal components and equilibrium moisture content was conducted. The results showed that the equilibrium moisture content increased with the increase of carbohydrates and reducing sugars in flue-cured tobacco, while the other chemical components in flue-cured tobacco showed little effect on equilibrium moisture content.