The work aims to prepare an indicator label for evaluating the freshness of fresh whitefish with the pigment extracted from roselle as a pH indicator. 1, 3, 5, 7 and 9 mL roselle ethanol solution (mass fraction: 2%) was respectively added to 50 mL chitosan-starch film solution to prepare five groups of food freshness indicator labels, and then affix them to the surface of three groups of 100 g fresh fish stored at 4 ℃. The food fresh-keeping film was used for the airtight packaging of fish and tray. The volatile base nitrogen, pH value and fish's odor, appearance, muscle tissue and other sensory changes were tested and evaluated in a period of 24 hours; and the color of the food freshness indicator label was measured and the sensory evaluation was made. The results showed that the indicator label turned from purplish red to grayish green when the addition of roselle pigment solution reached 7 mL, and the color gradually approached to green at the later period of the experiment with significant change. Roselle pigment can be used for fish freshness detection, which has a good indication effect.