The changes of color parameters including lightness value(L*), redness value(a*), yellowness value(b*), Chroma value(C*)and Hue Angle (H), the changes of chemical components and the relationship between color parameters and chemical components in lower, middle and upper leaves of flue-cured tobacco during bulk curing process were investigated to provide theoretical basis for optimizing the curing technology and for controlling the curing process precisely and intelligently. Results showed that, the color parameters in different positions of the flue-cured tobacco showed a consistent changing pattern, from the beginning of the curing process to the time when the temperature reached 42 ℃, the color parameters in the leave changed most remarkably, but the changes of upper leave were slower than that of the middle and lower leaves. The correlations between color parameters and chemical components were quite different among different leaf positions. There was no significant correlation between color parameters and total phenols, but there were good correlations between color parameters and reducing sugar and pigments. Reducing sugar in middle leaves had significant positive correlations with L* and a*, significant positive correlation with b* and C* and significant negative correlation with H. Chlorophyll-a and chlorophyll in lower and middle leaves and chlorophyll-b in middle leaves were significantly correlated to b* and C*, very significantly correlated to a* and H. Chlorophyll in upper leaves had significant correlation with a* and H. Carotenoid of lower and upper leaves showed significant negative correlation with a*, in middle leaves showed very significant negative correlation with a*, in middle and upper leaves showed significant positive correlation with H, in lower leaves showed significant positive correlation with H, and in middle leaves showed significant negative correlation with L*.