Abstract: A tea leaf color measurement system was established by using the scanner, color picker tool ColorPix and RGB color rules. The value of color difference was converted into CIELab color system parameters by the online tool ColorHexa and then the leaf colors of Typical Green, Yellow and Purple tea Germplasms were comparative analyzed through circular direction and radial direction methods. The results showed that the single leaf multi - point repeat value in radial measurement and the mid-ring position value in circular method had similar leaf color characterization. The 120 tea germplasms were randomly selected and measured for the brightness L^* and chromatic components a^* and b^*. The values of lightness L^* and color difference a^* and b^* between the two methods were significantly and positively correlated. However, when the facilitation and the efficiency of analysis were taken into consideration, it is better to use the color value in the mid-ring position by circular direction method. When the leaf color values of 120 germplasms were measured in the mid-ring position to draw the three-dimensional scatter plots, the mauve color group was effectively separated from the purple germplasms, which further proved the efficiency of the method to accurately identify specific leaf color germplasm.

Key words: tea plant, leaf color, color measurement device, quantitative description