Objective To investigate the color differences of enamel and dentin of natural teeth, so as to lay a foundation for reducing the color differences of natural dentin and core of all ceramic restorations. Methods X-rite Color i7 Spectrophotometer was used to examine the chroma value and chromatic difference (ΔE) of enamel and dentin of natural teeth (thickness 0.9 mm, 0.6 mm and 0.3 mm, n=30) . Results The L^* values (lightness) of enamel and dentin increased with the decrease of slice thickness, and the a^* values (red-green) and b^* values (yellow-blue) decreased with the decrease of slice thickness (P<0.05). The absolute L^*, a^* and b^* values of the dentin were significantly greater than those of enamel of same thickness (P<0.05). There were great color differences between enamel and dentin of different thicknesses, with the mean ΔE values within a range of 5.303-13.109. The color difference gradually increased with the thickness increase of enamel and dentin. The ΔE value of the enamel and dentin of the same thickness was 5.115 (0.9 mm), 5.855 (0.6 mm), and 6.053 (0.3 mm), respectively. Conclusion There is noticeable color difference between the enamel and dentin of natural teeth, and the difference increases with the increase of their thickness difference. The dentin has a more yellowish color and less lightness compared with the enamel. So each laminate of all ceramic restorations needs a shade selection for all ceramic restorations, and more attention should be paid on the color matching of natural dentin and core ceramic laminate.