The work aims to prepare a visual indicator label for monitoring pork freshness and explore its practical application with natural pigment from sappanwood as pH indicator. The indicator label was prepared with the pigment from sappanwood as indicator and qualitative filter paper as carrier. Colorimetric analysis and ammonia sensitivity analysis were conducted to test the indicating performance of the label, and the label was further applied in monitoring the pork freshness.Colorimetric analysis showed that the label changed obviously from yellow to dark red with the increase of pH value in the range of 4-12. Ammonia sensitivity analysis showed that the higher the ammonia concentration, the more significant and faster the color of the label changed. The application of the label in monitoring pork freshness showed that, with the deepening of pork corruption, the color of indicator label changed obviously from yellow to dark red, the ΔE value of the label showed a good linear relationship with pH value and volatile nitrogen (TVB-N) content of pork (R2=0.989 7 and 0.916 3, respectively), which could be used for monitoring pork freshness. With the natural pigment from sappanwoood as pH indicator and qualitative filter paper as carrier, an indicator label for monitoring the freshness of pork products could be constructed based on chromatic change or time required for the color change. The results of this study could provide reference for the construction of new natural pigment of indicator label for monitoring food freshness.