In order to find out the color variation of the theaflavin aqueous solution in the tea liquor, during the fermentation of the black tea, this experiment measures the light absorption value of tea liquor manufactured with different tea cultivars, fresh leaves with different tenderness and processed in different seasons and different fermentation time by using the spectrophotometer at 460nm wavelength. Results of the experiment showed that the light absorption value and its maximum value and the velocity of variation are different under the above conditions. However, the light absorption value of the tea liquor changed as low - high -low with the extension of fermentation time, which is in accordance with the variation of the theaflavin content during the black tea fermentation.